Implemented changes mentioned by @blizzz.
Ready to review it and for more corrections. As specially for the
"emergency break"

apps/user_ldap/goup_ldap.php:42
Corrected typo cheked to checked

apps/user_ldap/goup_ldap.php:67
removed unneeded lines

apps/user_ldap/goup_proxy.php:104
added $includeTopGroups to the array passed to handleRequest.

apps/user_ldap/lib/access.php:49
implemented something like a emergency break :)
But there I ran into a problem. (So if I wanted to check, that I don't
enumrate again and again and again through the same groups, I would
need a var that is the same over every function call. So I think I would
need a global var? But I saw in your codingguidelines (No global
variables or functions)).

apps/user_ldap/lib/access.php:50
Moved opening { one line up.

apps/user_ldap/lib/access.php:58
added a space infront of the { 

apps/user_ldap/lib/access.php:54
added a space infront of the { 

apps/user_ldap/lib/access.php:669
added a space infront of the { 

apps/user_ldap/lib/access.php:666
same as: apps/user_ldap/lib/access.php:49

apps/user_ldap/lib/access.php:888
changed comment, and added linebreaks so the codeline isn't too long.

apps/user_ldap/lib/access.php:900
same comment as for apps/user_ldap/lib/access.php:888

l10n/de/settings.po & l10n/de_DE/settings.po 
rolled back to first local history version during fork.

settings/templates/admin.php:162
added check that the option to only share with groups and subgroups is
only shown when user_ldap is enabled.

settings/templates/admin.php:162
Changed:
"Allow users to share with users in their groups and subgroups (LDAP
Only)"
To:
"Allow users to only share with users in their groups and subgroups
(LDAP Only)"