Replace `rust-bitcoincore-rpc`

Since [`rust-bitcoincore-rpc`](https://github.com/rust-bitcoin/rust-bitcoincore-rpc/) is unmaintained, we need to replace it. There's a couple options:

- [`bitcoind-async-client`](https://github.com/alpenlabs/bitcoind-async-client), from Alpen (async)
- [`corepc-client`](https://github.com/rust-bitcoin/corepc), 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."](https://github.com/rust-bitcoin/corepc?tab=readme-ov-file#contributing)).

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.