Add support for HeatBot 15L water heater (#4693)
* Add configuration for HeatBot 15L water heater
* Refactor YAML structure for heatbot 15L water heater
* Update water heater entity configuration
Changed the translation key for the water heater entity and updated the operation mode value.
* Remove name from energy sensor in YAML configuration and removed translation key
Removed the name 'Energy Usage' from the energy sensor configuration.