[TASK] Add backwards-compatibility for old BE modules

Handling of "&M" parameters is added back in order to make
the transition for Backend modules easier.

Resolves: #83800
Related: #82406
Releases: master
Change-Id: Iaa237b62254804d78314b48d80dfbea563fd7af4
Reviewed-on: https://review.typo3.org/55589


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Mathias Schreiber <mathias.schreiber@typo3.com>
Tested-by: Mathias Schreiber <mathias.schreiber@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>