Previously the richtext editor introduced the loss of the collision
avoidance feature.

Since the ticket thread is nested in a div now (required for inline videos
to be displayed correctly), the image hover caused the images to be shown at
the end of the thread entry body rather that its original location.

This means that drive-by mouse hovers, where the user likely did not intend
for the hover to actually popup the banner with the filename and download
button, do not trigger the popup. This patch changes the popup effect so
that it requires a 500ms hover before the popup is shown.

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

Remove ticket.min.js (users can minimize/compress files on thier own)

Use locktime (reply form hidden input) to auto-detect if locking is enabled without the need to ping the backend

Add print options supports - staff can now print a ticket thread without internal notes + select paper size on the fly

Protect againts cross-site request forgery attacks by requiring a special
form-field or header to be sent with requests that modify ticket system
data.

This meant a slight change to the AJAX ticket locking mechanism. It was
defined to lock with a GET request; however, GET requests are defined as
safe methods and should not modify backend data (such as a lock
acquisition). Therefore, the the lock acquire AJAX method was changed to
require a POST method.

Also remove old, no-longer-used staff panel include files