Remove ZHA device entity (#24909)

* move availability handling to device

* update last_seen format

* add battery sensor

* fix interval

* fix battery reporting now that it is a sensor

* remove zha entities and add battery sensor

homeassistant/components/zha/core/const.py

@@ -19,7 +19,6 @@ DATA_ZHA = 'zha'
 DATA_ZHA_CONFIG = 'config'
 DATA_ZHA_BRIDGE_ID = 'zha_bridge_id'
 DATA_ZHA_DISPATCHERS = 'zha_dispatchers'
-DATA_ZHA_CORE_COMPONENT = 'zha_core_component'
 DATA_ZHA_CORE_EVENTS = 'zha_core_events'
 DATA_ZHA_GATEWAY = 'zha_gateway'
 ZHA_DISCOVERY_NEW = 'zha_discovery_new_{}'
@@ -67,6 +66,9 @@ SERVER = 'server'
 IEEE = 'ieee'
 MODEL = 'model'
 NAME = 'name'
+LQI = 'lqi'
+RSSI = 'rssi'
+LAST_SEEN = 'last_seen'
 
 SENSOR_TYPE = 'sensor_type'
 HUMIDITY = 'humidity'
@@ -76,6 +78,7 @@ PRESSURE = 'pressure'
 METERING = 'metering'
 ELECTRICAL_MEASUREMENT = 'electrical_measurement'
 GENERIC = 'generic'
+BATTERY = 'battery'
 UNKNOWN = 'unknown'
 UNKNOWN_MANUFACTURER = 'unk_manufacturer'
 UNKNOWN_MODEL = 'unk_model'