Move HKC entity classes into entity.py (#76333)

homeassistant/components/homekit_controller/__init__.py

...tant/components/homekit_controller/alarm_control_panel.py

homeassistant/components/homekit_controller/binary_sensor.py

homeassistant/components/homekit_controller/button.py

homeassistant/components/homekit_controller/camera.py

homeassistant/components/homekit_controller/climate.py

homeassistant/components/homekit_controller/cover.py

homeassistant/components/homekit_controller/entity.py

homeassistant/components/homekit_controller/fan.py

homeassistant/components/homekit_controller/humidifier.py

homeassistant/components/homekit_controller/light.py

homeassistant/components/homekit_controller/lock.py

homeassistant/components/homekit_controller/media_player.py

homeassistant/components/homekit_controller/number.py

homeassistant/components/homekit_controller/select.py

homeassistant/components/homekit_controller/sensor.py

homeassistant/components/homekit_controller/switch.py