[BUGFIX] Handle docroot-relative paths in ResourceCompressor

Resolves: #89124
Resolves: #90689
Resolves: #88184
Releases: master, 9.5
Change-Id: I41b6c9d73346974cffb029551be5f987f9a09a79
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63714


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>