Turn Pypsa-Ariadne into Pypsa-DE

[lindnemi]

To do this we have to decouple the model from the Ariadne database.

Maybe provide a file with reasonable default input values and introduce a config option to switch from fully Open Source to Ariadne specific.

[lindnemi]

Looks like we do not have to decouple from the ariadne database, but just connect to ariadne1 database as a guest user. to do that you need to be logged out of ixmp (ixmp4 logout ). Furthermore, the model names changes slightly

[lindnemi]

• couple to public database
• provide public user instructions
• document changes to pypsa-eur
• rename repo
• resolve bundesstaaten
• prepare release
• do some advertisment
• add pre commit ci
• add validation CI