Feature Request: Add a -rpcwaittimeout parameter to limit time spent waiting

[barton2526]

Bitcoin merged this feature in June (bitcoin/bitcoin#21056):

Adds a new numeric -rpcwaittimeout that can be used to limit the
time we spend waiting on the RPC server to appear. This is used by
downstream projects to provide a bit of slack when bitcoinds RPC
interface is not available right away.

This makes the -rpcwait argument more useful, since we can now limit
how long we'll ultimately wait, before potentially giving up and reporting
an error to the caller.

I think it would be a welcome addition to the Gridcoin wallet. The caveat, however, is that in order to implement the above feature we also need upstream's rpcwait parameter. Reference bitcoin/bitcoin#3283.
Both of these will likely need to be ported together.