Use sqlite.org/sqlite, revert to sync api

[insipx]

the async backend is still on a branch, wasm-backend-async

the OpenMls storage trait is sync, so while xmtp_mls can be made 100% async (it's mostly async now anyway, other than the db/pool), the openmls trait can not, without significant refactoring of the openmls library

wa-sqlite is advantageous over the official sqlite wasm since its possible to define your own VFS in Javascript. This enables using browser-native APIs like IndexedDb/OPFS/etc or any combination of custom VFS. That's why wa-sqlite has such an extensive list of VFS' -- it's very flexible. Because of this, however, it exports a strictly async API. it's possible to make this api sync, but that would offer little benefit over using the normal sqlite compiled wasm. this also brings the API closer to whats in diesel, enabling more code sharing in the future.

the official sqlite wasm defines a sync api and only offers the use of OPFS as a VFS. It supports web workers, too. This fits requirements for getting xmtp_mls on web, and makes integration easier since no transition to async for db calls is necessary.

• removes diesel-async, wa-sqlite
• adds sqlite/sqlite-wasm
• removes all async/await