Only use field display when fetch value is not string

Pass name to Queue Column Annotation annotate routine

This commit adds the ability for DatetimeField to specify format string -
this is useful when the field display requires specific format different
from the system defined formats. For example during export.

This commit addresses longstanding memory and speed issues with ticket
export especially when exporting large set of tickets.

The implementation borrows heavily on Custom Columns, which introduced the
idea of using placeholder field to parse the data from query (db) instead of
making models to do the  parsing which led to related models getting fetched
too -- and hence the memory issues.

The commit also addresses caching of choices for selection fields and such
to avoid expensive trips to database for each row!

Conflicts:
	include/class.forms.php
	scp/js/scp.js

Tasks: Task visibility

issue: Session form-data Files

oops: Class GenericAttachment Not Found

This addresses an issue introduced with 4426 that references an undefined
class.

issue: Duplicate Page Requests

Misc. Fixes

This commit addresses a case where a large thread entry body (emailed) is
stored as a file, when fetching it we have to make sure we're only fetching
plain text/html and not attachment files.

This is necessary because ticket filters or API can set an invalid help
topic id. Either deleted or no longer active.

forms: Render Instructions

issue: Newly Added Queues

issue: Duplicate Personal Queues

This addresses an issue where newly added queues in the Admin Panel do not
show up in the list of queues nor in the ticket view. This is due to the
function that does not set any additional flags on queues if one already
exists.

This addresses an issue where personal queues are duplicated in the main
queue sub-list.

This addresses an issue where clicking Open, Post Reply, etc. more than once
whilst creating/responding to a ticket will generate duplicate requests.
This causes duplicate responses to be sent out or duplicate tickets being
created. This adds jQuery, on both Agent and User side, to disable the
submit buttons when the "Loading" popup appears so you cannot click the
button more than once.

This addresses issue 4493 where the system renders form instructions as
plain text instead of HTML. The data is saved in the db as encoded HTML and
upon pulling the data we do not decode it back to HTML for rendering.

issue: Existing User Registration

Creating Tickets with Attachments

This commit fixes an issue where we were not emailing attachments for initial responses when creating a Ticket.

issue: Default Help Topic Issue Summary

Implement Referral Internal Notes

accessibility: Screen Readable Actions

oops: Selection Search Bug

Email Name Format

Filter Action Send an Email Issue

This commit fixes an issue we had with adding a Filter Action to Send an Email. We had an option at the top for 'Default System Email', however, it did not have the Email ID or address for the system email and would throw an error if chosen. Now, we just retrieve the emails with their IDs and values with the Default System Email being the initial value selected in the list of options.

This commit further corrects issues where emails were being sent out with names being improperly formatted if the name format is set as 'Last, First' or if it has special characters.

This addresses an issue introduced with 4124 where searching for a Selection
Field with the criteria "does not have a value" throws an `implode()`
warning.

This improves accessibility by adding screen readable labels to ticket
actions that don’t already have them.