Kleisli Categories, Kleisli maps

[TOTBWF]

Description

This PR defines the Kleisli category of a monad, and proves that the category of Kleisli maps is weakly equivalent to the Kleisli category.

There are also a couple of chores in here: I've fixed some naming inconsistencies with lemmas for fully faithful functors. I've also refactored EM categories to be displayed.

Checklist

Before submitting a merge request, please check the items below:

• [x] I've read the contributing guidelines.
• [x] The imports of new modules have been sorted with support/sort-imports.hs (or nix run --experimental-features nix-command -f . sort-imports).
• [x] All new code blocks have "agda" as their language.

If your change affects many files without adding substantial content, and you don't want your name to appear on those pages (for example, treewide refactorings or reformattings), start the commit message and PR title with chore:.

[Lavenza]

Pull request preview

[plt-amy]

I've also refactored EM categories to be displayed.

:heart: