[Feature Request 🪶 ] Improve site readiness at end of terraform apply

[grayside]

Problem

When terraform completes, we present links to the user and no instructions. Presuming the user knows to click on firebase_url, they are likely to end up reaching a 404 page:

This page stayed up through multiple refreshes for more than a minute. Ultimately I added some querystring in case the 404 page needed cache busting to load, and at that point the loading page came up. The bare URL continues to be a 404 page without the cache buster. Possibly unrelated: the cache busted URL is stuck in the loading page. This is likely a separate bug.

Current Behavior

terraform apply is spinning up a GCE instance, which runs a script to deploy the firebase site. Presumably, this deployment process takes an unpredictable amount of time to complete & propagate, and this time extends beyond the total runtime of terraform.

Expectation

When the user navigates to a URL at the end of tf apply, the URL resolves to an element of the avocano app or content.

[grayside]

I went through another site deploy today, and again found this 404 page in another project. The site deployed as part of my the initial bug report is still stuck as a 404 page without a cache busting parameter.

[grayside]

Fixed on same terms as #64