WWW: Rewrite homepage

[mjherzog]

We need to rewrite the homepage to provide a general introduction to AboutCode and orientation for the rest of the website.
It is currently dominated by the many project info cards which make it hard to see anything else.
This rewrite needs to be coordinated with moving project info cards to their own section - see:

• WWW: Move project cards to a separate top-level section #143

[pombredanne]

Diagram(s) like that (made better) could help?

[mjherzog]

Closing because the Home page has been upgraded but I will open a separate issue to create a graphic as illustrated here.