Verify a signed message.
addressstringREQUIREDsignaturestringREQUIREDmessagestringREQUIREDcurl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"verifymessage","params":["address","signature","message"]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/true