If Bitcoin's already running, check if it's on the target version

Before launching Bitcoin, check if it's already running:
- if Bitcoin isn't running do the status quo (launch bitcoin)
- if Bitcoin is running, check the version
- if it's on the target version, don't launch it again
- if it's not on the target version, stop the current pid via `bitcoin-cli`, wait for it to stop, then do the status quo (launch bitcoin).