Split readme up into smaller files.

[RebeccaStevens]

The readme has become huge and hard to manage; it needs to be broken up into multiple smaller files.

[jonaskello]

Yes, perhaps we could look into using a format that will work with a site generator like readthedocs or something similar and have that published to github pages. Should I look into this or have you already started work on it?

[RebeccaStevens]

Sounds like a nice way to do it. I haven't done anything with regards to this issue. If you'd like to take this on go ahead :)

[jonaskello]

I investigated this and evalutated two options. One is to use jekyll, it is the most integrated way with github pages. However it involves ruby and I'm not using ruby for anything else so for that reason it was not a good option. I also found docusaurus which is based on nodejs and react and has github pages support. It seems like a good option.

However since we are now moving to eslint I'll focus my efforts there instead and at least initially try to follow how they do the docs over at typescript-eslint.

[RebeccaStevens]

I haven't had much of a look at docusaurus yet but on surface it looks quite good.

I think typescript-eslint's docs are done the same way as eslint so that sounds like a good way start :)

We probably can leave this repo as is.

[RebeccaStevens]

I just found docsify. Might also be worth looking into.