Create server integration tests for jgroups SASL auth

Create integration tests for jgroups SASL auth via DIGECT-MD5 and GSSAPI mechs. JGroups auth SASL auth is contained in following commits:
https://github.com/belaban/JGroups/commit/01100c4730cb3cb86a686bc8b2118edff6e15f71
https://github.com/belaban/JGroups/commit/fd0710f358594c1bdc73137ea05902e1fdff8a0f