Functional wish: Add heat index and wind chill

[StephanStS]

The node is good, thanks for working on it. It serves well for outdoor temperature based issues.
I would appreciate an extension with heat index and windchill. This shall give an idea what to expect when going outside.

I propose the following outputs:

• Heat index
  • Gives the "felt temperature"
  • See https://de.wikipedia.org/wiki/Hitzeindex#Berechnung
• Heat index status
  • Gives hints (4 warning levels)
  • See https://de.wikipedia.org/wiki/Hitzeindex#Warntabelle
• Windchill
  • See https://de.wikipedia.org/wiki/Windchill#Aktuelle_Berechnung_und_Tabelle
• Windchill status
  • See blue fields in table

For the heat index and heat index status I can provide a C code example.

In addition I would propose to go to version 1.0.0, in my opinion the node is stable enough for a 1.x.x version number.

[StephanStS]

See also flow "Calculate 'feels like temperature' for weather models".