Replace rust-bitcoincore-rpc #2049

Since rust-bitcoincore-rpc is unmaintained, we need to replace it. There's a couple options:

• bitcoind-async-client, from Alpen (async)
• corepc-client, from rust-bitcoin (blocking)

I have never used corepc, so not sure how that would go. Also, Tobin made it clear that it should not be used in production ("Please do not use corepc-client in production and raise bugs, issues, or feature requests.").

If we go with bitcoind-async-client, it would be necessary to implement any missing methods and types that we need there, or submit a PR that swaps it with corepc-types. We would also need to fork it and make a blocking version, or make this crate async all together.