- Complete rework of Database API
- Integration of Database API into Context
- Improvement of API

This commit is not a final implementation, just an intermediate backup.

Common / Context / Device / Service:
- Improvements in unitary testing
- Extended assertion validators tor testing
- Factorized service implementation code to improve testability, reusability and increase code coverage

Factorization of code between services and minor unitary testing improvements. (Not finished, it is just a backup)