Start 2i components during ns_server startup

The 2i components projector and indexer can be enabled during
node bootstrap by setting the environment variable ENABLE_2I.

Change-Id: Ic0cff242d79324ab4ba9875eb045b499f3ca1544
Fix query engine parameters to use dp3 version

Change-Id: I1d194c756a79b44028b3b286690d286012eabf61