docs: Refactor setup-recommended into includable files.

docs/development/setup/vagrant-resume.md

@@ -0,0 +1,13 @@
+When you're ready to work on Zulip again, run `vagrant up` (no need to
+pass the `--provider` option required above). You will also need to
+connect to the virtual machine with `vagrant ssh` and re-start the
+Zulip server:
+
+```console
+christie@win10 ~/zulip
+$ vagrant up
+$ vagrant ssh
+
+(zulip-py3-venv) vagrant@vagrant:/srv/zulip
+$ ./tools/run-dev
+```