Add retries to RPC

Currently we use `retry_operation` many times in our codebase like the following:

```python
await retry_operation(self.rpc(address=ws.address).gather, *args, **kwargs)
```

This is common enough that maybe we want to add it as a special keyword to `rpc` and the connection pool?

```python
await self.rpc(address=ws.address).gather(*args, **kwargs, retry=True)
```

This would conflict with using `retry=` as a parameter in any method. Maybe that's ok.