Refactor and fix sonar issues in FileBasedDiscoveries
Fix sonar issues in PushSubHubHub modules
Fix sonar issue in JSONRPCImporter
Add a FileBased config module in examples
Fix sonar issues in raspberry-pi importer
Add constants files to fuchsiaCore

Add MediaType, HttpHeaders, HttpStatus constants.
Use constants where needed, fix some sonar issues
Fix core pom.xml
Fix sonar issues
Reduce complexity in PubSubHubHub importer
Fix many sonar issues
Fix sonar issues
Fix issue in protobuffer importer

Protobuffer importer did not cleaned up the list of Service registration after stop
Add protobuffer importer test