PLAT-3942 - Add tests for MX Beans

Tests check that MX Beans register correctly through ComponentRepository
PLAT-3942 - MX Bean tests

Spring MBean annotations are not required
PLAT-3942 - Add MX Bean to allow query of subscription state

MX Bean added for StandardLiveDataServer so that an individual subscription can
be traced. Later iterations should increase the data available.
Merge remote-tracking branch 'origin/develop' into develop