[FEATURE] EXT:form - add file size validator

A new ExtbaseValidator called "FileSizeValidator" has been added which
is able to validate a file resource regarding its file size. The
validator is also available within the form editor.

Resolves: #82177
Releases: master
Change-Id: I04ae755b8632c473769fc7ae859c97d88c60b390
Reviewed-on: https://review.typo3.org/54135


Reviewed-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Tested-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Carlos Meyer <cm@davitec.de>
Tested-by: Carlos Meyer <cm@davitec.de>
Reviewed-by: Daniel Lorenz <daniel.lorenz@extco.de>
Tested-by: Daniel Lorenz <daniel.lorenz@extco.de>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>