[TASK] Deprecate ElementBrowserFramesetController

As far as I could find out, the 'browser' route target class
ElementBrowserFramesetController is unused for a while already.
I think it is unused since element browser and modal works in
v7 and v8, the FormEngine JS browserUrl route target is
always wizard_element_browser and searching for other things
like the bparams argument reveals no usages, either.
The patch deprecates the route and the controller.

Resolves: #86178
Releases: master
Change-Id: Ifed2e9210ef04f95944ddc2371e1ad616c73715f
Reviewed-on: https://review.typo3.org/58208


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>