completely refactor and modularize flake

modules/default/common/keyd.nix

@@ -0,0 +1,23 @@
+{ ... }:
+{
+
+  services.keyd = {
+    enable = true;
+    keyboards.default = {
+      ids = [ "*" ];
+      settings = {
+        main = {
+          rightalt = "overload(altgr, rightalt)";
+	        capslock = "overload(control, esc)";
+	      };
+	      altgr = {
+          a = ''macro(compose a ")'';
+          o = ''macro(compose o ")'';
+      	  u = ''macro(compose u ")'';
+      	  s = ''macro(compose s s)'';
+	      };
+      };
+    };
+  };
+
+}