[TASK] RTE: Migrate event handling to jQuery

Migrate non-widget event handling to jQuery.
Migrate custom events to jQuery.
Migrate ExtJs tasks to plain JavaScript.
Migrate ExtJs key maps to jQuery.

Releases: master
Resolves: #63572
Change-Id: I3828c24ad3ce7a5193d42ba76819cf09e47456c9
Reviewed-on: http://review.typo3.org/35043
Reviewed-by: Stanislas Rolland <typo3@sjbr.ca>
Tested-by: Stanislas Rolland <typo3@sjbr.ca>