Draft: TYPO3 v13 suppot

[dmitryd]

This is still work in progress.

The following changes are included:

• Rework backend module according to TYPO3 recommendations
• Fix calls to deprecated methods
• Fix wrong storage pid that prevented fetching of services on any page
• Move templates and partials around because simplified TYPO3 API does not allow custom locations

The extension can be requested like composer req "websedit/we-cookie-consent:^5.0" due to branch-alias in composer.json. It should be removed before merge.

TODO:

• Frondend tests