- implemented generic Context queries
- added Slice to object_factory

Consolidating commong fixtures in a single file at the root of the tests folder. Updating ECOC'22 and OFC'22 tests to use it.

Fixing some imports and branching a fixture file for each test case so that they can have particularities.

Including the validation of creation of KPIs and their values to the OFC'22 test set. Also consolidating the fixtures into a single file in the root of the 'src/tests' folder so that all tests can import from it.

- Renamed OldBigNet scenario to BigNet
- Updated JSON descriptor builder scripts
- Generated descriptor files for scenario
- Updated definition of functional tests