fix: disable sourcing set-environment in zsh

This has broken nix shell, and it's not needed
when qtile is not used

fix: set system environment in zsh

Zsh had environment from the wm, qtile.
That contains python environment that
I do not want. This sources the environment
of the system, without the qtile env

feat: add alias for locating binaries

chore: update to nixos-unstable

feat: make default git branch main

feat: add git user configuration

fix: fix issues

feat: add initial configurations