refact: API props in camelCase

src/aura_engine_api/rest/controllers/internal_controller.py

src/aura_engine_api/rest/controllers/public_controller.py

src/aura_engine_api/rest/models/clock_info.py

src/aura_engine_api/rest/models/health_log.py

src/aura_engine_api/rest/models/play_log.py

src/aura_engine_api/rest/models/playlist.py

src/aura_engine_api/rest/models/playlist_entry.py

src/aura_engine_api/rest/models/timeslot.py

src/aura_engine_api/rest/models/track.py

src/aura_engine_api/rest/swagger/swagger.yaml

src/aura_engine_api/rest/test/__init__.py

src/aura_engine_api/rest/test/test_internal_controller.py