Bring signrawtransactionwithwallet up to date #21
Description
Currently unimplemented.
signrawtransaction has been obsoleted in favor of signrawtransactionwithwallet and signrawtransactionwithkey on bitcoin core, since v0.18.0.
We should support signrawtransactionwithkey in lbcd, and implement signrawtransactionwithwallet in lbcwallet