Tutorial (general + CLARIN.SI) and citation information

[harisont]

I gave #29 some more thought and, for now, only added the about page a very minimal tutorial (only one "universal" examples + links to language docs), as well as more prominent citation information.
At the end of this mini-tutorial, there is a paragraph that says "For some more advanced examples, follow this link", where "this link" redirects to different places depending on cfg.system_name, namely (I propose):

1. Korp: a post yet to be written on the Språkbanken's blog (nice side effect: I don't have to write a separate blog post about the research visit ;)
2. CLARIN.SI: whatever @kajad prefers! It can be both a separate internal page or something like 1.
3. no particular config: the step-by-step Grew tutorial

Thoughts?

[Niklas-Deworetzki]

This looks good to me!

I think the advanced examples link should be configurable as well, instead of hard-coding some case distinction. And there we can use the Grew tutorial as a fallback.

Feel free to merge once you're ready!

[kajad]

Sorry for not reading this sooner than replying to #29 . This should also work, but I would prefer it being a separate internal page as part of cqp-tree site rather than an external blog/page.

[harisont]

Ready to merge this and close #29 as far as I'm concerned!
But I thought maybe @kajad wants to proofread my explanations around her examples for Slovene, so I installed this version on Språkbanken's demo server for you to take a look: https://demo.spraakbanken.gu.se/cqp-tree