[TASK] Introduce composer manifest checks

The extension manager now provides a new module,
which allows an integrator to display all available
extensions with composer deficits, like missing
composer.json or missing extension-key.

The new module informs about the deficit and
automatically generates a valid composer.json.
proposal. In case no composer.json exists, the
corresponding ext_emconf is sent to a new TER
endpoint (https://extensions.typo3.org/composerize).
This endpoint then generates a new composer.json
proposal by resolving all dependencies.

Furthermore, a new report is added to EXT:reports
which also informs about such extensions by directly
linking to the new EM module.

This helps especially in non-composer-mode installations
to ease the upgrade path for future TYPO3 versions which
(hopefully) will rely on composer.json only for e.g.
PackageStates.php.

Resolves: #93931
Releases: master, 10.4
Change-Id: I1230363d5d03e03bff39e7070faf4e331532a292
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68778


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Helmut Hummel <typo3@helhum.io>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Jochen <rothjochen@gmail.com>