Update to (somewhat?) dendritic pattern

Heavily inspired by https://github.com/Doc-Steve/dendritic-design-with-flake-parts.

> Atomic commits? Never heard of them!

modules/programs/git.nix

@@ -0,0 +1,16 @@
+{
+  flake.modules.nixos.git = { pkgs, ... }: {
+    environment.systemPackages = [ pkgs.git ];
+  };
+
+  flake.modules.homeManager.git = {
+    programs.git = {
+      enable = true;
+      settings.user = {
+        email = "weckyy702@gmail.com";
+        name = "Weckyy702";
+      };
+      #TODO: signing
+    };
+  };
+}