Offload State Resolution into Rust

[reivilibre]

The aim is to get it off the reactor thread, stop it holding the GIL and ultimately get better performance.

Things to consider:

• [ ] we might need to move Event into Rust (Erik has a branch that started this; it's quite old but at the same time it's probably still a good start) #16503
• State res makes DB accesses and those can't be moved into Rust until #16501 is sorted — but there are pieces of code around the DB calls, where we manually yield to the reactor for instance, that are hopefully ripe for moving over

[TRISHAHALDER]

please assign me this issue.

[clokep]

please assign me this issue.

We generally don't assign issues outside of the core team.

For this issue in particular -- it likely needs a bit more discussion and a plan, it isn't ready to just work on.