Remove instances of "Coming Soon"

Let's leave experimental code in place, but we want to change the language we're using to be more direct to developers.

- [ ] Remove Contentful from the home page installation section
- [ ] "Considering" frameworks and sources should be something like "Open for Contribution" (ideally shorter) with details about the issue, support for getting started, etc.
- [ ] Remove Vite example page (other examples we can add)