Proto:
- Minor corrections in context.proto

Common:
- Minor corrections in common.orm.backend
- Improved definition of orm.Model class with get_instances and get_references
- Extended ORM unitary tests with get_instances and get_references

Context:
- Implemented missing methods in ContextClient
- Started to implement new Context data models using ORM.
- ContextModel functional using ORM and gRPC.
- Arranged old code file placing

- Added methods to automate metric class generation
- Added decorator for servicer RPC methods to add metering and logging features automatically
- Added unit tests
- Minor imptovements in context unit testing

- added unit testing into automated unit testing processes

Modifying the test and coverage execution files to accomodate the case where the project is located in any folder.