[TASK] Improve performance of Bootstrap/PackageManager

This patch is a combined patch which tries to address
the findings from the Bootstrap/PackageManager/ClassLoader
performance analysis.

Resolves: #56934
Resolves: #56310
Resolves: #56331
Resolves: #56341
Resolves: #56538
Releases: 6.2
Change-Id: I269159906534f58eff59973ab30e170fadac10e4
Reviewed-on: https://review.typo3.org/28329
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny