[FEATURE] Enable/disable cascading deletion of child elements

Deleting a record will also delete all child records,
which are configured as type inline (field, list) within.
This patch adds a behaviour configuration option "enableCascadingDelete"
which is by default treated as true. If set to FALSE or '' or 0
deletion of inline child records will be disabled.

Resolves: #50391
Releases: 6.2
Change-Id: I7462e7721cd140880edeea82664ce4721aea63a7
Reviewed-on: https://review.typo3.org/22551
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind