Mkdocs basic setup + learn section

[Ellipse0934]

Solves #44

From the project root run a mkdocs serve for a preview.

TODO:

• [X] Github Pages
• ~~[ ] Examples section~~

Mkdocs vanilla is quite powerless. It can't do basic things like substitution using macros. So either we will need an extension to do this OR shift to a more modern stack. For now I will add scripts to do the hacky work. Like copying examples/*.cn -> docs/examples/*.md

Ultimately, newer standards like Asciidoc make sense but their tooling is limited at the moment.

I am also quite annoyed at them for not giving an option to disable the footer OOTB.