Finish setting up documentation

[BSchilperoort]

In #18 mkdocs was initialized and a documentation page made.

However, to finish the docs we still need to:

• [x] Set up readthedocs (or use GH pages?)
• [x] Add workflow integration for the docs
• [x] Add more info to the documentation, logo, etc.

[BSchilperoort]

The docs have been set up. I added the URL to the repository.