Added parameters to configure a list of node group processes

Added MASTER_NODE_PROCESSES and WORKER_NODE_PROCESSES parameters
to HDP plugin config. The default list of processes that will be launched
on a cluster remains as before, but an ability to configure it is added
in order to test different configurations.

Change-Id: Id100b1dbabd89f1a4bdae22f0c45639faff77077
Merge "Added parameters to configure a list of node group processes"