FC-39 FC-34 FC-42 FC-40 FC-41 FC-32 Added blue-green deployment support

Added system message handlers to manage application instance lifecycle, for application participating in blue-green deployment. Also added some preliminary changes for configuring number of worker threads independently for each message listener thread pool.

Signed-off-by: Steffan Westcott <steffan.westcott@clicktravel.com>
No. The responsibility of this class is to apply flow control, which has two components in its implementation:

* Apply rate limitation
* Control the start of REST request processing (as part of application instance lifecycle)

PlatMan includes management of rate limtation, but not management of application instance lifecycle.