[!!!][TASK] Deprecate ext:backend class AbstractModule

The internal / experimental class ext:backend/Module/AbstractModule
doesn't do much useful stuff: It only instantiates ModuleTemplate
in it's constructor which forces all inheriting classes to call
parent::__construct(). The processRequest() method with its
dispatcher code is never used in core, but superseeded by routing
configuration via Configuration/Backend/Routes.php.

The patch removes given AbstractModule usages and markes the
class as deprecated. The patch is slightly breaking in cases
an extension extends AbstractWizardController and additionally
uses the initialized moduleTemplate property.

Change-Id: Iee36e1787a6dc2a1affb3625983ccb6450589481
Resolves: #82689
Releases: master
Reviewed-on: https://review.typo3.org/54312


Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@t...>