Riven v3 tracking issue

[MingweiSamuel]

• [ ] Generate schema code in Rust, possibility for (semi-)automatic updating #83
  • Do we want to keep the generated code tracked in the main branch, or if not how can we have nice diffs between generations? (generated in a different branch?)
• [ ] Figure out an API to unify the new try_ methods from #79
• [ ] Cleanup the error types (maybe use thiserror as a helper)
  • Remove source_reqwest_error
• [ ] Adjust rate limiting
  • [ ] Move away from using sleep "rejection sampling" to obtain rate limits, use a proper waker queue/semaphore instead
  • [ ] Examine possible race conditions when obtaining rate limit tokens due to not holding on to locks
• Figure out what other breaking changes to make!