Resolve L2SS-1197 "Add antenna set"

CDB/stations/dummy_positions_ConfigDb.json

docker-compose/schemas/definitions/observation-settings.json

...trol/tangostationcontrol/common/observation_controller.py

...tangostationcontrol/configuration/observation_settings.py

...tationcontrol/tangostationcontrol/devices/antennafield.py

...stationcontrol/tangostationcontrol/devices/observation.py

...ontrol/tangostationcontrol/devices/observation_control.py

...tegration_test/default/devices/test_device_observation.py

...n_test/default/devices/test_device_observation_control.py

...ontrol/integration_test/recv_cluster/test_recv_cluster.py

...stationcontrol/test/common/test_observation_controller.py

.../tangostationcontrol/test/configuration/_mock_requests.py

...oncontrol/test/configuration/test_observation_settings.py

...gostationcontrol/test/devices/test_antennafield_device.py

...tangostationcontrol/test/devices/test_observation_base.py