[TASK] Streamline LinkBrowser controller

- Use native typehints instead of doctype
- Add return types
- Use strict types
- Use DI: abstract class uses inject* methods,
  inheriting classes use constructor DI
- Improve array annotations for phpstan level 6
  (not yet detected)
- Remove method comments with no added value
- Use str_starts_with
- Move abstract and public methods to the top

Some minor refactorings along the way:
Get "richtextConfiguration" directly from parameters
array in BrowseLinksController.

Resolves: #96763
Releases: main
Change-Id: I547b50617a080e988b2b69417f0d5bce5ed98c62
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73323


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>