[FEATURE] Re-Design the AdminPanel

Major refactoring of the admin panel:

- Split content in modules and sub-modules
- Modules are indepent and pluggable
- Modernized design
- Better extensibility
- Clearer separation of page and module settings

For more information see .rst files.

Resolves: #84584
Releases: master
Change-Id: Iad4dfbc485e1c1280bbdb2e7fb0dcdc9f90bf537
Reviewed-on: https://review.typo3.org/57084


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>