Also moves rust toolchain to a nightly equivalent of stable 1.87, in
order to allow for existing rustfmt configs such as imports granularity
to be used.
Includes a blog system which fetches whitewind blog posts stored on an
ATProto PDS:
* Optional feature to enable the blog system
* Updated build script to generate client from lexicons
* Fetching system along with in-memory caching and data validation