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/java-mode/debug

@@ -0,0 +1,6 @@
+#name : debug
+# --
+if (mLogger.isDebugEnabled()) {
+  mLogger.debug(String.format("${1:result}=%s", ${2:result}));
+}
+$0