[FEATURE] Introduce service to handle multiple flash message queues

Currently there is just one system wide flash message queue. This
unfortunetly leads to problems using flash messages in extbase as
one cannot address a subset of messages to a dedicated extension/
plugin/controller/action. To resolve this this patch introduces a
flash message service that handles multiple queues which falls
back to the known behaviour by default.

Releases: 6.1
Resolves: #44593
Change-Id: I445499f7936d51ddd5ee89fc537974685b1843c7
Reviewed-on: https://review.typo3.org/17571
Reviewed-by: Andreas Wolf
Reviewed-by: Stefan Neufeind
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn