LDAP Util: Only use PagedResults controls if the server advertised to support them

Currently the LDAP util tries to use PagedResults controls for every connection, regardless if the server supports them or not, and deals with the exception by complaining about the server not supporting them and issuing a second request with PagedResult controls.

This should be changed to
 - first try to get a list of the supported controls from the server
 - only using a PagedResults control in the request if the server advertised to support them
 - and only complaining and falling back to the behavior described above if the server claims to support the controls, but doesn't.