[TASK] Add caching layer for getTargetPidByPlugin

The function getTargetPidByPlugin should use an internal
cache for reducing the load to the DB

Change-Id: Iec5ab7bc75b5a50c05bd814594dd3568a5beac73
Resolves: #36053
Releases: 6.1
Reviewed-on: https://review.typo3.org/19821
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer