Reworked static website

Fixes #6

New website can be found in this repository: https://github.com/SFTtech/openage-website

This PR just tracks the status of the tasks.

Tasks:

[ ] Landing Page: Finish writing texts
[ ] Feature page: Collect most important features, write small abstracts for it
[ ] Download page: Links for Linux package repositories, fix buttons (aim for div instead of table) for nightly builds
[ ] FAQ: Questions need to be answered
[ ] Get involved: What can be done overall? Where are contributions possible?
[x] Documentation/Development page: done, just linked to doc
[x] Carousel: Text explaining what we see, why
[x] Impressum / privacy: done
[X] Helpers enquiry: Link to github
[X] Core glossary: was copied from Wiki
[X] About page: No content for it right now

Later:

[X] Media page: We should update after the new converter tbd
[X] News blog: will be possible on the new side, not activated now, as we can do that when we want to have a first entry tbd
[X] Changelog: Blog like entries? tbd

I think the website should be delivered from the gh-pages branch then, or is it possible to let the domain point to a subfolder structure?

SFTtech / openage-pr