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`).

This addresses an issue with pull 4472 where disabling the Submit button
does not submit the Input value for the button. This affects the
installation of plugins, where the Install Path is not sent therefore the
plugin is not installed. This clones the original submit button, hides it,
then displays a dummy disabled Submit button which will submit the value and
prevent dupe posts.

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 commit makes sure that when the Reset button is hit, we only reset File Upload Field attachments for the specific form we're on.

Ex: Viewing a Ticket as an Agent and switching between 'Post Reply' and 'Post Internal Note'. If you had an image in the Post Reply file upload but switched to Post Internal Note and hit Reset, only the text/attachments on the Post Internal Note tab would be cleared.

(Improves upon #4369)

- Add space between column headers and sort arrow
- Fix sorting by 'Subject' column
- Fix redactor issues with 'Reset' button
	- Make sure text within redactor is cleared correctly
	- Make sure we don't keep attachments if Reset
- Make sure redactor is reinitialized where needed

This fixes files disappearing when uploading multiple files. Only one file
at a time is uploaded to the server.

This pass also makes a stride at adding correct punctuation and making error
phrases consistent.

If the subject field is something crazy, such as an HTML field, ensure that
the layout of the ticket queue is preserved and properly truncated.
Furthermore, ensure that the HTML is properly rendered on the client and
staff ticket view pages.

This patch adds to the client interface the ability to filter tickets on the
client portal by help topic, as well as a "clear" feature to clear search,
sort, and filter options.

* Log events for AJAX collaborator list edits
* Avoid extra selects for inline image handling
* Avoid using htmLawed to add target="_blank" and class="no-pjax" to links
  in the ticket thread
* Cache instances of IntlDateFormatter; seems expensive to set up
* Cache filetypes Yaml in APC if available
* Cache I18n::getDefaltLanguage() in the request
* Avoid extraneous usage of Model::_inspect and Model::$meta
* Add aggregated query support to the ORM
* Lazily compile SQL query for InstrumentedLists
* Apply `select_related` setting when setting up InstrumentedList instances
* Slight optimization in SqlCompiler::getField
* Avoid double compiling Sql annotations in the ORDER BY clause
* Cache Thread::getEntries
* Break out event types for ThreadEvent for more legible code
* Eliminate one query from Ticket::loadDynamicData
* Fix ticket number bolding if already answered
* Use dependent subqueries for ticket statistics in the queue page, which is
  significantly faster for large data sets (like hundreds of attachments or
  thread entries)
* Fixup sidebar layout on client knowledge base pages

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.

This includes adding support to the Redactor editor to force the width of th
editable content to match the width of the displayed content on the client
portal. Also, the landing page displayed on the client portal is themed
(css-class wise) to match that of the Redactor content similar to the FAQ
and thread-entry designer boxes as well.

Chosen has a problem being rendered in a dialog box with overflow:scroll,
because the content of the dropdown widget is truncated with the scrollable
content of the dialog. Select2 addresses the issue by placing the dropdown
box in the <body> and absolutely positioning it into place.

This patch adds Content-Language and <link rel="alternate"> information to
the client interface for better integration with search engines. It also
adds @lang attribute to the <html> element and various input, textarea, and
richtext boxes for better spell check integration and accuracy.

Register change event on underlaying textarea on focusout. This is necessary
for event listener e.g locking system.