Support building the site with nix build

[Samasaur1]

This would make CI simpler

[Samasaur1]

I think this might cause issues with the Git plugin though

[Samasaur1]

There should be some way to inject self.rev and self.shortRev though

[Samasaur1]

Here's where the git hash is done:

samasaur1.github.io/_layouts/default.html

Lines 58 to 62 in 09e557f

	{% if jekyll.environment == "production" %}
	Built off of <a href="{{ "https://github.com/Samasaur1/samasaur1.github.io/tree/" | append: site.github.build_revision }}">commit <span class="text-monospace">{{ site.github.build_revision | truncate: 7, "" }}</span></a>
	{% else %}
	Local build (last commit <span class="text-monospace">{{ site.data['hash'] }}</span>)
	{% endif %}

Easiest way to deal with this is probably to just remove that git plugin (or conditionally remove it for Nix builds) and then inject the hash into site.data