[TASK][DOC] Additional FAQ entries for SSO and eu_ldap

Change-Id: I9d65a7a93a10f724ccc271e0cf66d8f4103badc3
Reviewed-on: http://review.typo3.org/32186
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>