Update the monorepo tutorial with more detail, and restructure so Domains are automagically detected

[echohack]

I ran through this tutorial tonight and thought it could use a bit of extra detail.

When you try to add your domains first before deploying a project with a bound port, you will have to manually define the port, then later either set the env.$PORT variable or recreate the domain entirely so the correct port that the service is bound to is automagically detected. I swapped the order of the tutorial so you don't have to repeat these steps (which can be confusing) and instead just bound it correctly the first time. That should make it alot easier for folks to get the idea behind the basics of wiring up a monorepo.

[brody192]

Hello!

Thank you for your PR!

For some context, in the past when you created a domain without a deployment it would not ask for a port and since the frontend and backend in the example both listen on $PORT it would all just work.

But since that has changed and setting a port is required, I completely agree, this restructure does make far more sense now.

LGTM!