* Move AwaitUtxos next to the other shared writeable state requests
* Rename ReadResponse::Utxos to ReadResponse::AddressUtxos
```sh
fastmod Utxos AddressUtxos zebra*
```
* Rename an out_point variable to outpoint for consistency
* Rename transparent_utxos to address_utxos
```sh
fastmod transparent_utxos address_utxos zebra*
```
* Run AwaitUtxo without accessing shared mutable chain state
* Fix some incorrect comments
* Explain why some concurrent reads are ok
* Add a TODO
* Stop using self.mem in AwaitUtxo requests
* Update state service module documentation
* Move the QueuedBlock type into the queued_blocks module
* Explain how spent UTXOs are treated by the state
* Clarify how cached Chains impact state read requests
And move repeated comments to the module header.
* fastmod ChainUtxo BestChainUtxo zebra*
* Add an AnyChainUtxo request
* Make AwaitUtxo non-blocking
teor