tests

Common:
- Renamed common.metrics to common.rpc_method_wrapper
- Moved ServiceException to common.rpc_method_wrapper
- Implemented High-Level ORM methods to simplify Database handling

Context:
- Added flag to auto-populate fake data for testing purposes
- Added fake objects for testing purposes
- Minor corrections in ORM Database Models
- Reimplemented gRPC Servicer methods using HighLevel ORM helper methods
- Implemented complete unit testing of gRPC Servicer
- Added Message Broker to enable distribution of database events
- Implemented gRPC GetEvents methods
- Modified default config values to support larger number of persistent connections for events streaming
- Reimplemented Context REST Resource to re-use gRPC Servicer and prevent duplicating code

Automated Tests:
- Reactivated common and context unit tests