- added exposition of redis-tests service for testing with Redis backend
- moved delete logic from Context Servicer to ORM components
- added support for constraints of different kinds

- Arranged .gitignore & .gitkeep files in common proto folder
- Created specific run_tests_locally script for Context component
- Moved imports from *.proto folder to common.proto folder
- Adapted common.tools.object_factory to new proto definitions for ConfigRule and Constraint
- Extended common.tools.type_checkers to new proto definitions for ConfigRule and Constraint
- Removed context's genproto.sh script
- Adapted Events generated to new timestamp data type
- Minor code and linting fixing

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

Context:
- ORM models completed and tested
- Deactivated unneeded code-linting warnings
- Improved coding of fast_hasher method
- Added test unit for fast_hasher method
- Improved organization and structure of test units

Common:
- added ORM helper function get_related_instances
- minor modifications in ORM framework

Proto:
- field/message/enum renamings in context.proto to normalize notation

Context:
- Expanded service/database/Models.py into separate models to facilitate coding
- Completed implementation of Get/Set/List/Remove methods for Context, Topology, Device, Link, and EndPoint; also completed for relation models between topology and device/link, and ConfigModels
- Implemented test units for Get/Set/List/Remove methods for Context, Topology, Device, Link, and EndPoint
- Implemented skeleton for Get/Set/List/Remove methods for Service.
- Added Tools.py with helper methods to fimplify handling of enums between ORM and gRPC messages.