hosts: move gnupg into a module

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

hosts/modules/gnupg/default.nix

@@ -0,0 +1,9 @@
+{ ... }:
+{
+  programs.gnupg = {
+    agent = {
+      enableSSHSupport = true;
+      enable = true;
+    };
+  };
+}