ISPN-4012 Mark mass indexing tests as unstable
Temporarily disable REST security integration tests until  ISPN-4407
ISPN-4412 Fix failing embedded security integration tests
ISPN-4415 Provide correct Managed executor facade and fix XSLT

* Correct executor thread factories needed to be provided according
to the executor being plugged. Scheduled ones need a different facade.
* Fix an XSLT issue so that custom Hot Rod endpoints are added
correctly.
ISPN-4414 Compatible failover request load balancer for HR clients
ISPN-4414 Update documentation to use new request balancing interface