Facade returns an unmodifiableMap.

Change-Id: I3897a039384f5ea671110f189b0bdec9c09e4c20
Removed unnecessary proeprties in plugin definition.
These properties are retrieved through Settings as being declared with -D on call.

Change-Id: I368a803183036c1e2529ef307844aa6f1805deca
Merge pull request #2 from mildis/split-plugin

Split plugin
Add anonymous logic in GerritConfiguration

Change-Id: If10e47f77d0933f67a1dff314c2a9e946836faf5
Reworked for injection.
GerritConfiguration, GerritConnector and GerritFacade now implements BatchComponent.

Change-Id: I398c28a886e4a544e44940b76ea958955b6932b2