Revert "Simplify Git services. Clean cashes on external pushes."

This reverts commit d2ee1cc362fe2542a5714d5507d427f8eaaf40a5.
Revert "Remove unused methods from GitHttpServerRegistrationHandler."

This reverts commit 6c66f3cb5cda9650a437db8baa2526ae29f945ef.
Remove default cardinality MANDATORY_UNARY
Join all @References on a single line for better grep support
Add SCR support classes and unify usage of the maven-scr-plugin
LocalGitService, LockService - ok
Make all services implementen Validatable
Add referenceInterface to every @Reference
Initial set of validating references
ValidatingReference for MBeanServer
ValidatingReference for ConfigurationAdmin
ValidatingReference for CuratorFramework
ValidatingReference for ContainerRegistration
ValidatingReference for DataStoreRegistrationHandler
ValidatingReference for DataStore
ValidatingReference for GitDataStore
ValidatingReference for PortService
ValidatingReference for FirewallManagerFactory
ValidatingReference for CredentialStore
ValidatingReference for GitService