[Dynamic connection properties] Server REST circuit breaker

During first development iteration, we've introduced a simple request to Meta API: we need to provide a circuit breaker implementation instead in order to make it resilient.

Class involved: ConnectorPropertiesHandler

See reference implementation here: https://github.com/syndesisio/syndesis/blob/master/app/server/endpoint/src/main/java/io/syndesis/server/endpoint/v1/handler/connection/ConnectionActionHandler.java#L90-L156