[FEATURE] Converter from EXT:eu_ldap

A converter is integrated in Extension Manager with the UPDATE! script
to ease the migration from eu_ldap's configuration records.

The conversion is not able to ensure a proper conversion of user group
configuration but it does as much as possible.

Resolves: #60990
Change-Id: Ic082a41e68ae67a6c52de8e1de65571552f840b4
Reviewed-on: http://review.typo3.org/32194
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>