Fix README

[kba]

The README is still from the theme we based this on, apparently. I'm all for attributing other people's work, but the README should be mostly about Infolis.

[kba]

Hastily rewritten. @infolis/web-design What do you think?

[zuphilip]

Good for first information. I suggest further:

• I think a link to the CC-BY would be appropriate and maybe specify the version of the licence.
• Somehow the connection to the web services and the whole dynamic part of the website should be made more clear (where to find the code for the other parts of the websites).