Accessing the fakeified repository directly is more straight forward.

This caused problems where new content was only shown on explicit reloads

Replaces short-term Gitea instance on `code.kummerlaender.eu`.

The main reason for implementing this more complex setup is that Gitea
both lacks in features in areas that I care about and provides distracting
features in other areas that I do not use.

e.g. Gitea provides multi-user, discussion and organization support but doesn't provide
Atom feeds which are required for [Overview](https://tree.kummerlaender.eu/projects/xslt/overview/).

This is why exposing [gitolite](http://gitolite.com)-managed repositories
via [cgit](https://git.zx2c4.com/cgit/about/) is a better fit for my usecases.

Note that gitolite is further configured outside of Nix through its own admin repository.

As a side benefit `pkgs.kummerlaender.eu` now provides further archive
formats of its Nix expressions which simplifies Nix channel usage.

Updating various hashes and regenerating the whole system config for
each content update doesn't feel quite right.

Instead nginx now serves Nix store links placed in the home directory
of a separte `public` user.This user maintains local clones of page
source repositories and generates them using their respective Nix
expressions. This allows for greater flexibility while maintaining most
of the benefits of declarative configuration. Re-building static site
derivations may also be automated using e.g. post-receive hooks.