Common:
- Added missing object factory methods for constraints

Context:
- Adapted unitary tests to new constraint object factory methods

Service:
- Adapted unitary tests to new constraint object factory methods

PathComp-Backend:
- Deactivated health probes since it causes problems in backend REST server

PathComp-Frontend:
- Correct unitary test constraints for SP algorithm
- Adapted unitary tests to new constraint object factory methods
- Fixed instantiation of ShortestPath and KDisjointPath Algorithms
- Ignore unknown constraints in Algorithm request composition

- 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

- monitoring/test_monitoring.py: provides a basic testing skeleton
- monitoring/requirements.in/.txt: updated with pytest
- monitoring/genproto.py: added instructions to import generated Python modules using "from . import ..." instead of "import ..."; otherwise, pytest and other possible modules doing imports might complain.
- monitoring/monitoring_server.py: packed start_server and stop_server functionaity to simplify test definition, minor formattings, bug resolutions and improvements in package import.
- monitoring/monitoring_client.py: minor formattings, bug resolutions, and improvements in package import.