Don't set Base User and Base Group when Base DN was detected, would case problems but does not provide any benefit. also make sure that empty string is saved instead of false for multiline values

LDAP: dissolve LDAP Basic settings, move Login Filter to Advanced and clean up Advanced settings, too. This is all done via Wizard, now.

Ldap Wizard: find out whether server supports memberOf in LDAP Filter and disable group chooser if not

Fixed zip download button for unlimited filesize in public mode

update 3rdparty submodule

Move OC_Connector_Sabre_Server to expected location.

Added missing condition to check whenever allowed zip size is unlimited.

Fixes #3717

only call shell_exec if enabled