Consider using Netlify's preview deploys for front-end PRs

[toolness]

We recently migrated WoW to a client-server architecture (https://github.com/JustFixNYC/who-owns-what/pull/306) whereby the front-end is served via Netlify while the back-end is in Django. One of the neat things this enabled was the use of Netlify's preview deploys on every front-end PR, which made it really easy to try out proposed front-end changes. The preview deploys always used the staging (aka demo) back-end.

While such a client-server separation isn't ideal for the Tenant platform because of its use of server-side rendering, it would be cool if there was a way for the front-end to exist independently of the back-end solely for the purpose of being able to easily stand up and try out prospective front-end changes.