This commit fixes an issue where using MPDF to print Tickets did not work if the PHP version was < 7.0 because MPDF called the random_int function which is only available for PHP 7.0+. Now, we check the PHP version before printing, and if it is less than 7.0, we use the rand function. If it is >= 7.0, we continue to use the random_int function.

* Require keyword search term to be 3 words or less
* Show keyword search option on Advanced Search dialog

- Create a new database patch to add a new Event table, use event_id instead of state for thread_events, and remote the 'state' column in thread_events
- Create the Event class
- Use event_id instead of state for Thread Events

This commits adds ability for agents to configure public queues.

* Customize Columns
* Set default sort & quick filter
* Add supplemental filters (criteria)

To support above features this commit also addresses confusing Advanced
Search UI to make it intuitive when dealing with a Saved Queue vs. Saved
Search vs. Adhoc Search

Add ability to add sticky export fields for queues.

Add the initial concept of thread (tickets & tasks) referral.

* Agent & Team
Referring a ticket to an agent or team - is just like assignment without
actually assigning. If referred agent doesn't have access to the ticket's
department then they'll only have view access.

* Department
This is like assigning a ticket to the entire department. Meaning agents who
have access to the referred to department will now see the ticket - what
they can do with the ticket will depend on the assigned role in that
particular department.

It's important to note the ticket will technically be still the
responsibility of the primary department. Transferring the ticket is the
sure way to relinquishing the responsibility.

* Auto Department Referral via email
This will happen if an email is sent to multiple departments. For example an
email with TO: support &  CC: billing will result in the ticket getting
routed to "support" department and "billing" getting a referral of the same
ticket. This allows both departments to have visibility of the ticket -
which is not possible at the moment.

Add the initial concept of thread (tickets & tasks) referral.

* Agent & Team
Referring a ticket to an agent or team - is just like assignment without
actually assigning. If referred agent doesn't have access to the ticket's
department then they'll only have view access.

* Department
This is like assigning a ticket to the entire department. Meaning agents who
have access to the referred to department will now see the ticket - what
they can do with the ticket will depend on the assigned role in that
particular department.

It's important to note the ticket will technically be still the
responsibility of the primary department. Transferring the ticket is the
sure way to relinquishing the responsibility.

* Auto Department Referral via email
This will happen if an email is sent to multiple departments. For example an
email with TO: support &  CC: billing will result in the ticket getting
routed to "support" department and "billing" getting a referral of the same
ticket. This allows both departments to have visibility of the ticket -
which is not possible at the moment.

This patch implements Nathan's mockups for adding sorting options to the
custom queues. The sort drop-down feature was added for v1.10. This patch
adds the complex sort dropdown back into the custom queue feature, but also
makes the sorting options customizable.

This allows for less work when designing new queues. The column design—the
data definition, annotations, and conditions, are saved with the column. The
heading, sort order, and width are set when the column is associated with a
queue. This means that changing the behavior of a particular column will
mean not having to redo work for each queue that uses the column.

* HTTP Option: TRUSTED_PROXIES (default: <none>
To support running osTicket installation on a web servers that sit behind a
load balancer, HTTP cache, or other intermediary (reverse) proxy; it's
necessary to define trusted proxies to protect against forged http headers.

* HTTP Option: LOCAL_NETWORKS (default: 127.0.0.0/24)
When running osTicket as part of a cluster it might become necessary to
white list local/virtual networks that can bypass some authentication
checks.

* Validate CLIENT_IP to make sure it's a valid IP address.

This is required for system requests such as email piping. Since a user is
not logged in for the request, the system locale will not be set and text
might get corrupted based on the PHP configuration.

Fixes #2910

Change orgs listing to ORM
Add cdata tables support for users and organizations

(rather than deleted after install)

This patch attempts to query or detect the Olson style timezone
(e.g. America/Chicago) from the database. This is preferred over the
previous code as the previous code would always consider the current
database GMT offset rather than the GMT offset of the date being converted
(which might be on the other side of a DST transition).

Add a tab for tasks
Add mass action for tasks

This is necessary to allow objects to register data views on the fly.

This patch includes a slight database migration, and adjusts the
functionality of a few core components.

  * Move collaborators from the ticket to the thread.
    This concept allows collaborators on any object which has a thread,
    including tasks.

  * Add flags to the thread entry
    This will allow flagging thread entries for different purposes.
    Initially this can be used to flag the original message of a thread in
    case a ticket / thread is created without an initial message.

  * Lock becomes more of a utility
    The lock is now disconnected from the ticket and is a separate utility.
    Separately, the ticket and task objects can have a reference to a lock
    object. Furthermore, when submitting some activities to tickets, the
    lock is verified to be owned by the respective agent, and the lock code
    must match a current lock code. The code is rotated on each acquire()
    call to guard against double submissions.

  * Collaborator is an ORM model
    The TicketUser class is broken up now so that the collaborator instance
    can exist apart from a ticket. Email message ids are now generated for
    collaborators without respect for a ticket so that collaborators can be
    properly supported on any thread.

This patch rebases filters into a row-based layout and redesigns the filter
apply method to be more extensible. It also redesigns the UI to be more
dynamic and to allow for actions to be added without database modification
and actions can also have complex configurations.

Help topics can now specify one or more additional forms to be included on
the help topic and can also specify the sort order of those forms.
Furthermore, individual fields can be disabled per help topic, so that
unnecessary fields can be omitted when necessary, per help topic.

The disabled flag is recorded along side the field data so that the field
will not be accidentally added to the form later automatically. There is no
interface in this commit to enable a field which was disabled by the help
topic when ticket was created.

Introduce the concept of tasks. Tasks are to do list that can be attached to
any object e.g Ticket.

Use generic attachment table for all attachments system-wide.
Drop thread entry attachment table

Detach conversation thread from ticket to make it more generic. Any object
can now have its own thread complete with entry type and attachments.

Use generic attachment table for all attachments system-wide.
Drop thread entry attachment table

Detach conversation thread from ticket to make it more generic. Any object
can now have its own thread complete with entry type and attachments.