Discovery (#74)

* add support for Home Assistants MQTT discovery

* add format_topic a flexible separator

* add mqtt discovery for miflora

* add mqtt discovery for mithermometer

* add mqtt discovery for thermostat

* add unit to illuminance in miflora

* switch to 'away_mode_command_topic' instead of 'away_command_topic'

* revert changing the date format

* add mac to ientifiers and change the id generation

* add mac to ientifiers and change the id generation on thermostat

* add mac to ientifiers and change the id generation for mithermometer

config.yaml.example

@@ -8,6 +8,9 @@ mqtt:
   availability_topic: lwt_topic
 
 manager:
+  sensor_config:
+    topic: homeassistant
+    retain: true
   topic_subscription:
     update_all:
       topic: homeassistant/status