Implement DeploymentEventSources in samples using SharedInformers

[adam-sandor]

Currently the DeploymentEventSource in the Tomcat and Memcached samples is implemented using a Watch. Fabric8 now supports SharedInformers which have a nicer API and cache the requested objects. To properly utilize this caching the DeploymentEventSources should be extended with a get method which would be used by the Controller to fetch resources from the cache. I think the SharedInformer itself shouldn't be exposed to the Controller but maybe that's not a bad idea either.

[csviri]

Now this is possible with InformerEventSource out of the box.

[csviri]

this is done, see: #659