Move frontend editing to a system extension
As a first step toward improved frontend editing in TYPO3 4.3, we should move the existing frontend editing ino a system extension to preserve compatibility.
The only part that should actually move to this system extension is the "view" code from t3lib_tsfebeuserauth and tslib_cObject code for drawing edit panels and edit icons. The remaining "controller" code from t3lib_tsfebeuserauth can be refactored into a standalone controller for frontend editing.
At a later date, we'll add a new system extension with the necessary view code for the improved frontend editing.
(issue imported from #M9615)