The two timeouts for the server and client, are essentially different:
- In the case of the server it should be a lower value to avoid clients
clogging up connection slots
- In the case of the client it should be a high value to accomedate slow
responses from the server, for example for slow queries or when the
lock is contended
Split the options into `-rpcservertimeout` and `-rpcclienttimeout` with
respective defaults of 30 and 900.
