Add documentation directory

[srid]

1. Add a directory ./docs where application/library specific documentation will be stored.
   • In the template repo itself, this directory can store documentation for haskell-template and "recipes" like #33 (the user can replace them with their own docs)
2. Provide .#docs-live that runs Emanote live server and .#docs that builds the statically generated site; like https://github.com/srid/emanote-template
3. Move the bulk of README.md to ./docs; and link to the latter from the former.

(Example: https://github.com/EmaApps/ema has ./docs)

[srid]

Before we do this, I probably should release Emanote to Hackage (to avoid having to build it all locally; and instead rely on nixpkgs cache).

https://github.com/EmaApps/emanote/issues/153

[srid]

Before we do this, I probably should release Emanote to Hackage

Or we could write the docs anyway and use nix run to run Emanote on them (without nixifying it in flake.nix). Announce it in a blog post and then https://github.com/haskellweekly/haskellweekly.

[srid]

It may not actually be desirable to force the template users to keep (or manually remove) ./docs. Similar to #48, we could just add to documentation telling people how to host Emanote-based docs for their project?

[srid]

I'll do this in srid.ca

https://github.com/srid/srid/commit/e3b8c3b622caea39380024f984440af9460d512e

[srid]

https://srid.ca/haskell-template