hosts: move doas to its own module

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

hosts/programs/doas/default.nix

@@ -0,0 +1,16 @@
+{ ... }:
+{
+  security = {
+    doas = {
+      enable = true;
+      extraRules = [
+        {
+          groups = [ "wheel" ];
+          keepEnv = true;
+          persist = true;
+          setEnv = [ "PATH" ];
+        }
+      ];
+    };
+  };
+}