nix: yeet skrott, massive module modifications tm, wrap package and more

Sorry for the kinda big commit that does everything at once

This change does the following:
- yeets skrott and skrot-specific settings from the NixOS module,
- adds a bunch more settings and generalizations to the NixOS module,
- adds two VM NixOS configurations for interactive testing
- wraps the nix package so that `less` is always present in `$PATH`
- yeah, that's about it

kthxbye

.gitignore

@@ -7,3 +7,5 @@ dist
 test.db
 
 .ruff_cache
+
+*.qcow2