## What
Delete static client-side SDK docs in favor of generating them at
build time.
- Add a separate list of `clientSideSdks` to `readme-fns`.
- Use sdk type to determine which generation directory it goes into
- Replace manual sidebar category with autogenerated one
## Why
This does the same for client-side SDKs as was done for server-side
SDKs in https://github.com/Unleash/unleash/pull/2858
(Supersedes #2859)
