Add option to enable/disable basic DCL and/or DTCL

Add option to enable/disable basic DCL and/or DTCL

The cars stress test is a very appropriate place to measure the effects
of DCL and DTCL on a very long list.  This change adds a few RPC
implementations in order to do the following:

1) enable DCL
2) disable DCL
3) enable DTCL
4) disable DTCL

This change includes very basic DCL/DTCL implementations, which just log
a message at trace level (off by default but there for ensuring the
onData*Changed(...) method is actually called.

The existing clustering-test-app behavior doesn't change at all;  these
new RPC(s) do not need to be used, and the added Listener implementations
are not registered listeners by default.

Change-Id: I6fcec6cd8c0a082e815561e88b325a55022ad2af
Signed-off-by: Ryan Goulding <ryandgoulding@gmail.com>