feat(packages/rebuild): move rebuild script to a package

packages/rebuild/default.nix

@@ -0,0 +1,16 @@
+{ lib, pkgs, ... }:
+pkgs.writeShellScriptBin "rebuild" # sh
+''
+if [ ! -f "flake.nix" ]; then
+echo "flake.nix not found in current directory. exiting..."
+exit 1
+fi
+
+git add . && \
+nixos-rebuild switch --flake . --use-remote-sudo && \
+echo "=== opening test shell. ===" && \
+echo "=== exit = commit       ===" && \
+echo "=== exit 1 = abort      ===" && \
+$SHELL && \
+git commit -a
+''