Semantic models, colour-code sources

[Reitse]

We've stumbled too often on errors that were caused by connections to a wrong environment. Think a production environment where there's still a link to dev. It would be great if we could get a colour coded list of connections to make it easier to spot that a connection is tied to dev, test or prod. 

It's fine that we have to define the colours ourselves, the ability to do so would help a lot!