add single port/service getters in Component
add getter and setter in ComponentPorts
factorise checkPorts in ComponentService also separate req and prov ports
add flush method and comment ComponentService class
add parentConfig in Component
add flush calls to the configuration super parent

This call needs to be removed in a further version by using the
observer pattern.

Also add getters on prov and req ports associated to the service.
add Configuration empty flush methods