Docs: deployment

After talking with @formidableamy I think here's our goal:

- Production URL is https://formidable.com/open-source/react-native-owl/
- Staging URL is https://formidable-com-react-native-owl-staging-PR_NUMBER.surge.sh/open-source/react-native-owl/
- Localdev URL is https://localhost:3000/open-source/react-native-owl/

We'll plan to use https://github.com/FormidableLabs/formideploy which out-of-the box gives us per-PR deploys with deployment notifications and links in PR and takes care of the production deploy. ( _Note_: deploys of this project will be completely independent of formidable.com deploys or any other project )

Work to get there:

- [x] Reconfigure docusaurus to build to `/open-source/react-native-owl/` instead of `/`. (I'm assuming docusaurus can easily do this).
- [ ] Hook up `formideploy` to CI, replace placeholder deploy stuff, etc.
- [ ] Add `formidops` user, GH CI user, and add secrets to this repo.
- [ ] Make necessary changes in `formidable.com` website to accommodate the new site.
- [ ] Clean up the `website` Docusaurus template docs (e.g. shouldn't mention deploy because we do it our way)

I'll try to get started on this this week so we have a staging site to look at by Monday.