Add option to check share ACL's when listing directories

If a file or folder in a directory doesn't have read permissions they
will not be shown

Note that enabling this option incurs a performance penalty additional
requests need to be made to get all the acl.

Additionally the acl resolving logic is fairly primitive at the moment
and might not work correctly in all setups (it should error to showing
the entry)

Signed-off-by: Robin Appelman <robin@icewind.nl>