Deactivated some Device monitoring functionality partially implemented to enable a functional commit into develop.

- Adapt component and unitary tests to support configuration environment variables

- Final version of Context service ready for integration tests
- Integrated REST API read-only methods
- Updated test units for gRPC and REST API interfaces
- Improved flag for pre-populating database with fake testing data
- Combined Redis within Context POD

Common:
- reorganized Database API to enable extension of Context API with entities (e.g. Service)
- solved minor bugs in Database API

Context and Device services:
- rearranged services and unit tests according to mentioned Context API changes

Service service:
- initial release (under development, this is just a backup of code)