TYPO3 Core

Changes in this diff make it possible to configure FlexForms like normal TCA forms. Whole configuration can be done via TSConfig. And single FlexForm fields can also be disabled via group access lists.

Possible are: ============================================
- remove complete flexform tabs
- change flexform tab title
- remove single fields from a sheet (tab)
- change label of a single field
- change size, type, minitems, ... of a single field
- add, remove, keep and rename items in a select field

Syntax: ============================================

TCEFORM.tt_content.pi_flexform.[ext_key].[sheet_key] {

1. Remove complete sheet (tab)
   disabled = 1

1. Change sheet title
   title = LLL:fileadmin/locallang.xml:new_title

}

TCEFORM.tt_content.pi_flexform.[ext_key].[sheet_key].[field_key] {

1. Change label
   label = LLL:fileadmin/locallang.xml:new_label

1. Change configuration
   config {
   size = 20
   minitems = 1
   ...
   }

1. Rename select items
   altLabels {
   item = label
   }

1. Add select items
   addItems {
   item = label
   }

1. Remove select items
   removeItems = item1,item2

1. Filter select items
   keepItems = item1,item2

}
(issue imported from #M16334)