Added legion's user key. Added git signing. Started moving to common

modules/shared/common/default.nix

@@ -0,0 +1,24 @@
+{
+  config,
+  configurationName,
+  lib,
+  ...
+}: {
+  settei.user.config = {
+    programs.git = {
+      enable = true;
+      difftastic.enable = true;
+      lfs.enable = true;
+      userName = "Nikodem Rabuliński";
+      userEmail = lib.mkDefault "nikodem@rabulinski.com";
+      signing = {
+        key = config.settei.sane-defaults.allSshKeys.${configurationName};
+        signByDefault = true;
+      };
+      extraConfig = {
+        gpg.format = "ssh";
+        push.followTags = true;
+      };
+    };
+  };
+}