* Add Water Heater entity to MQTT
* Adding tests for Water Heater
* Remove duplicate line and unneeded var declaration
* Remove target temp range and away mode
* Move common Temperature Control conf to const
* Remove unnecessary platform schema and temp check
* Add common value template key test
* Use MqttTemperatureControl in Water Heater
* Move operation mode out of MqttTemperatureControl
* Remove unecessary attribute declaration
* Remove default min/max temp and auto init attr
* Fix mqtt water heater initial temp conversion
* Make async_set_temperature common
* Fix init temp comment
* Merge value_template_keys into get_with_templates
* Remove unnecessary operation_mode overriding
* Add async_set_temperature to water heater
* Fix docstring comments
