[FEATURE] Introducing a BooleanValidator.

A validator for boolean fields, which takes an option to set expectations.

Resolves: #45880
Releases: 6.1
Change-Id: I2aaf7bec8847483646a8562e7ea3da416d088381
Reviewed-on: https://review.typo3.org/18512
Reviewed-by: Stefan Froemken
Tested-by: Stefan Froemken
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring