introduced new resource with mocks of methods for sending messages, connecting and disconnecting from clients
extracted the serverDetails list into an variable which can be reused.
introduced new interface for factories of ProtocolBootstraps
implemented new factory which allows to obtain instances of protocol bootstraps, based on passed protocol
basic test for ProtocolBootstrapFactory
moved the registry to static final field
javadoc additions.
bunch of refactorings which introduce new abstraction grouping ServerDetails and Netty details for accessing servers.