Creates an unsigned tx for Bitcoin to send a single, specific UTXO to a selected destination.

How-to use:

• adjust config in index.js
• use prevTxId, vout and inputSat from a utxo you want to spend
• set destAddr for the receiver
• set minFeeRate (will be used from inputSat)
• execute: node index.js
• review and sign the resulting unsigned tx