Finalize the inputs of a PSBT. Signs and finalizes where possible.
psbtstringREQUIREDextractbooleanoptionalcurl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"finalizepsbt","params":["psbt_base64"]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/{
"psbt": "cHNidP8BA...",
"hex": "0200000001...",
"complete": true
}