Fix crashes compiling language packs on PHP 7

This fixes PHP issues compiling language packs with PHP after version 7.

Conflicts:
	include/client/header.inc.php
	scp/js/scp.js

issue: New Ticket Field Permissions

Issue: Mass Assign

issue: SubQueues Hide PersonalQueues

issue: Remove Referral Borked

This addresses an issue where removing a Referral from the Manage Referrals
modal just loads and loads, never actually removing the referral. This is
due to the AJAX URL containing an extra `/` causing an "Unsupported URL"
error.

This addresses an issue where creating a ticket as an agent and selecting a
Help Topic does not show the Issue Summary or Issue Details fields. This is
due to us passing 3 parameters instead of 1 as an array. This combines the
params in one array and only passes the array as a param.

This addresses an issue where adding SubQueues hides PersonalQueues. This
was due to the variable `$childs` being reset in the sub-navigation
template.

This commit addresses an issue where a Department might have the Ticket Assignment option set to All Agents, but when trying to mass assign Tickets, only Department Agents were shown in the list.

Note: If mass assign is done on Tickets with different Departments that have different Ticket Assignment rules, Tickets will only be assigned to the Tickets that are allowed the assignment.

PHP 7.2 Compatibility

jq: Update jQuery UI References

jq: Update To jQuery-3.3.1

This commit makes osTicket compatible with PHP 7.2

Conflicts:
	include/class.filter.php

This pull request is wayyyy overdue. This updates jQuery and all related
files to the latest jQuery release (3.3.1). This also adds a new script
called jQuery-Migrate that maintains older functions needed for a few things
(eg. `filedrop.field.js`).

- Pull latest code from osTicket
- Fix Filter ORM compatibility issues that resulted from merge

Oops: Modify 0 in Short Answer Field Fix

This updates the references to the old jQuery UI filename to the new
filename. (this needs #4672 merged first)

Fixes an unexpected side effect of Pull Request #4652

profile: Reply Redirect

Conflicts:
	scp/login.php

Issue: Can’t use “0” in Short Answer Field

This commit fixes an issue where a Short Answer Field would show as Empty if the value saved in it was '0'

Issue: Edit Export Column Heading

issue: Task Response With Collaborators

issue: Scrollable Quickfilters

Task Collaborators

Issue: Duplicate Search Results

Improve the Staff login

Issue: Tasks Within Tickets

This pull adds a Profile Setting for Agents to choose where to redirect
after replying to ticket. The two options are Queue (redirect to queue to
work on other tickets) or Ticket (redirect back to same ticket to continue
working) with the latter being the default. The setting is configurable for
each Agent in the helpdesk.

issue: Hide Task Loading Overlay

This addresses an issue where having more than 30+ choices for a Quickfilter
makes the dropdown run off the page causing some choices to be hidden. This
makes it to where if you have more than 20+ choices we will make the
dropdown a fixed height and make it scrollable.

This addresses a fatal error when adding a new response to a Task with
Collaborators. When we implemented the MailingList for Users/Collaborators
we forgot about the little Task Collaborators (poor little guys). This adds
a new function called `getRecipients()` to `class Thread` that utilizes
MailingList instead of UserList. This also adds two new functions to `class
Util` that retrieves the User’s `user_id`.