Refactor KnowledgeBaseImpl

It is required to review the KnowledgeBaseImpl and lower the technical debt accumulated on it by:

1. Remove unnecessary duplicated methods that at the moment are there only for backward compatibility reasons.
2. Review the locks and in particular check if some of them can be removed since now the kbase changes are enqueued.
3. Review the rules/packages addition lifecycle emitting events before and after them (and in general reviewing the existing events).