Add Emacs desktop provisioning and dev toolchain packages

Install Emacs and copy the desktop .emacs.d config so the editor setup is managed with the rest of desktop dotfiles. Add vterm/build/debug dependencies plus C/C++ and Go tooling needed by the configured workflow.

dotfiles/desktop/.emacs.d/snippets/yaml-mode/k8service

@@ -0,0 +1,14 @@
+#key : k8s/service
+# --
+apiVersion: v1
+kind: Service
+metadata:
+  name: ${1:foo}-service
+spec:
+  type: ${2:NodePort}
+  ports:
+    - port: ${3:80}
+      targetPort: ${4:80}
+
+  selector:
+    ${5:webkind}: ${6:colour}