Add alert levels

[metbril]

The domoticz plugin provides alert levels

https://github.com/Xorfor/Domoticz-Buienalarm-Plugin

Add support for sensors for level and text to prevent users having to create template sensors themselves.

[nelbs]

that should be a nice PR 😄

[gieljnssns]

Zou inderdaad mooi zijn, maar echt bitter weinig tijd voor...

[StevenLooman]

Kan dit niet met een Automation?

[ShadowJonathan]

@StevenLooman no, the sensor doesn't expose values in the future, and it only stops at the next point that any rain falls.