[FEATURE] Split file permission for be_users and be_groups

Since TYPO3 6.0 you can set specific file and folder permissions by
userTSconfig. This patch adds a new field for every table to be able to
set detailed access in the backend record. Any userTSconfig will take
privilege over user and group data. An update step converts the
old binary values to string list.
Deprecated functions to support the binary values of the old fields
are removed completly. Unit tests were adapted.

Resolves: #52716
Resolves: #50574
Releases: 6.2
Change-Id: I064887c60e215e9c394d484a4afd3faef51ee324
Reviewed-on: https://review.typo3.org/24613
Reviewed-by: Alexander Opitz
Tested-by: Alexander Opitz
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel