Some fix for PHP 7,2 https://github.com/osTicket/osTicket/issues/4237

This addresses the issue where files were being deleted before being sent
out in Agent responses. This was due to a bug in the query that gets the
orphaned files. This query was getting files created within the last 24
hours not after the last 24 hours. The query also had another bug that
would use the time from PHP instead of MySQL which could cause issues.
This updates the query as per @greezybacon's suggestions to delete
orphaned files that were created more than 24 hours ago.

This addresses an issue where the Upgrader will sometimes use an outdated
cached object and throw an error. This adds a the function to clear the
Model Cache every time the Upgrader runs an Upgrade Patch to get fresh
objects.

This addresses an issue where the User’s account status is always 'Active'
in the Organization list no matter what their actual status is. This adds the
account status to the user query which adds the correct status to the Users’
account.

This addresses an issue where Outlook adds weird (and seemingly random)
_MailEndCompose tags to the email body which turns unwanted content into
links. This adds the _MailEndCompose tag to Format::sanitize() so it
will be removed from the email body.

Encode html entities of cached form data

This commit addresses an SQL injection vulnerability in ORM lookup
function.

* ORM implementation failed to properly quote fields, used in SQL
statements, that might originate from unsanitized user input.

* AttachmentFile lookup allowed for key based SQL injection by blindly
delegating non-string lookup to ORM.

This addresses an issue where updating a Task does not change the
`updated` column in the database. This adds a line to change the `update`
column when updating a Task.

This addresses issue 3782 where clicking Print on a Task gives you a blank
popup that hangs. This is because the Print button was being treated as a
Task action when it is actually not one. This adds a ternary operator to
give the proper Task Actions the `task-action` class and gives the Print
button no class.

This addresses issue 3815 where searching by User's phone number doesn't
work in v1.10. This adds phone number search capabilities for the User
Directory and User Search popup in v1.10.

This addresses an issue where expired sessions would not be removed from
the database. This caused the session table to fill up and create
unnecessary issues. This adds a cleanup method to remove all expired
sessions from the database.

This addresses issue where upon deletion of a form field and all its
entry values, the field record wouldn't be deleted from the `form_field`
table. This links another issue where you can't delete a list if its
been a field before. This is due to the list delete() function that
checks for list field records in the `form_field` table.

This is necessary to force a particular timezone on a DateTimeField entry.
If timezone is not set then user's timezone is assumed.

Address edge cases where timezone mixups happens on DateTimeField

Allow datetime field to be timezone agnostic (not timezone aware) to display
the timezone used to set the field. The timezone of the last user or agent
that edited the field is used.

This fixes an InconsistentModelException error when editing thread
entries with inline images. The fix assumes that inline images are
re-attached when a new ThreadEntry is created and the body is copied
from the previous entry. Only the non-inline attachments need to be
moved in the update query.

This addresses issues #1964 & #3668 where $cfg might be null and cause a
non-object error. Check if $cfg is set, if not return the default
en_US language.

Fixes syntax error introduced with commit 71a6b2a0 & 6e0ddf2e

minor change fix the translation page url

Changes 'Permisions' to the correct spelling 'Permissions'.

Move orphaned tasks on department deletion to the default department

Display Loading Overlay when posting a response or a note to a ticket.

Can not update list item abbreviation because update() method is
expecting 'abbrev' key so this corrects the key.

* 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.

Encode html chars on helpdesk title

Defer to agent's timezone on due date `datetime` selection instead of
defaulting to GMT.

Fix case where filter applying 'Use Reply-To Email' filter action
triggers a reprocessing loop that exhausts php memory.

Fixes missing due date on task create caused by invalid datetime format sent to db.

Use class instead of id on form element that triggers overlay on submit.

Address cases where incoming email doesn't have message-id or references

Allow closed thread to be reopened when when is passive mode

Add support for threading email conversations happening outside the system.
Autoresponders are paused when threading is on passive mode. Alerts may
still go out to agents as configured.

Account for agents' name format setting when sorting agents.