Clarify/Expand on framework support

[dabeeeenster]

JS SDK's are used in a huge variety of runtimes:

• Vanilla JS
• Client side frameworks (e.g. React, Vue, Angular) with multiple versions and paradigms
• Hybrid client/server side frameworks (e.g. Next.js)
• Mobile devices (e.g. React Native, Ionic)
• And others!

It would be good to clarify what support, if any, we provide to each of these runtimes, as well as if there are any specific affordances (e.g. additional API interfaces etc) to working with each one.

A lot of this work could/would be just documentation, but occasionally it might be necessary to add additional interfaces/hooks etc.