This commit removes xpack dependencies of many xpack qa modules.
(for some qa modules this will require some more work)
The reason behind this change is that qa rest modules should not depend
on the x-pack plugins, because the plugins are an implementation detail and
the tests should only know about the rest interface and qa cluster that is
being tested.
Also some qa modules rely on xpack plugins and hlrc (which is a valid
dependency for rest qa tests) creates a cyclic dependency and this is
something that we should avoid. Also Eclipse can't handle gradle cyclic
dependencies (see #41064).
* don't copy xpack-core's plugin property into the test resource of qa
modules. Otherwise installing security manager fails, because it tries
to find the XPackPlugin class.