This addresses a long-time issue of the famous `DB Error #1062` when
uploading an Inline File to a Draft. The issue is that the system does not
check if an Attachment record exists before creating a new one. We create a
new Attachment record, we go to save it, and the system errors out because
that record already exists. This adds a check to see if the Attachment
record already exists and if so we use that instead of creating a new one.

This commit ensures that we will always get the correct attachment name regardless of if the file content is the same. Additionally, it ensures that the file_ids for attachments are compared in the correct order (elseifs)

- Make sure we keep attachments in the session even if the page refreshes to display an error message
- Reverse the array of files to be id => name instead of name => id
- Make sure we retain the old ticket or task id if we encounter an error while trying to create a ticket or task from a thread entry
- Make sure we have a valid fileId before returning file info
- Make sure we can still add files for Canned Responses (id and name flip issue)
- Make sure we can still add attachments to Internal Notes for Tickets and Tasks

This addresses an issue where uploading a file you’ve uploaded before but
renamed is not saving the new name in the Attachment table.

Previously, the create method was used to create a new instance of an orm
model (which would later result in an INSERT when persisted); however, some
classes require or utilize varying parameters to their create() method,
which PHP7 considers an error. Methods in subclasses must be defined with a
calling signature compatible with the parent class.

This patch shifts the concept of model creation to the constructor. Now, the
constructor of ORM models is required to be compatible with that of
ModelBase class. Now that most models do not define a constructor, this is
much easier to control, and much more logical.

Also, remove an issue where assignments on a relationship field to an
instance of a super class of the foreign model would raise an error. This
was previously addressed by re-classing the instance in the
ModelInstanceManager::getOrBuild(); however that design would create
multiple instances of the same object in memory, which defeats one of the
primary design concepts of the ORM. This patch addresses the issue by
allowing super-classes of the declared foreign model in relationship
assignments.

This commit attempts to remove all coding standard warnings emitted by PHP
7.0.

Also fix several javascript errors on ticket edit

This patch (which needs further development), introduces an extra field to
the %attachment table to store a file's name, in the event that two files
with the same content are stored in the database with differing names. In
such a case, the name is stored in the %attachment table. This allows the
attachment to specify a different name each time the same file is attached
to something in the system.

* Fix crash saving a page (regression)
* Fix red banner deleting a department
* Fix crash deleting a knowledgebase article

* Fix attachments not sticking on new dynamic form entry
* Fix attachments not sticking on thread post validation error
* Fix missing inline images in FAQ article viewing
* Fix missing inline images in FAQ article printing
* Fix crash rendering sidebar in staff faq view with attachments
* Rewrite GenericAttachments to be an ORM object
* Port CannedResponse to ORM
* Fix attachments not being displayed when editing a FAQ article
* Fix squirly empty blue box on faq articles with no attachments

Looks like Redactor finally quit double urlencoding() the autosave requests
Also, remove ALL drafts after 14 days.

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 converts the central file and threading classes over to use the
ORM.

  * Fix missing attachments join for Category (fixes #1654)
  * Fix crash on user account registration
  * Fix save button on user account (fixes #1655) — regression from bebc2d79

This script adds a single download script, 'file.php', which provides access
to files of all types to all users. It uses a HMAC signature system with an
expires time, which allows signed URLs to be sent to external users.

This also fixes an issue with the Http::cacheable() method, where the
last-modified and Etag headers were not properly compared, which resulted in
permanent cache misses by the client.

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.

Including language-specific attachments

Auto-detect inline attachments
Attached keepers to canned reply

This is a regression introduced somewhere along the way in the new storage
API system for osTicket.

Allow a callback function to be used to determine if an error should be
logged and an alert mailed

Process inline attachments in thread entry and support inline images in
piped emails

Support inline images across the system, with draft support

Migrate to a single attachment table
    That way we don't need a new table for everything we need to attach an
    inline image to (like a signature, for instance)

Add richtext support for internal notes

Implement images on site pages

* Image paste in Redactor
* Make non-local images optional
* Placeholder for non-local images
* Fix local image download hover
* Don't re-attach inline images