Disallow using addresses in createmultisig
Make createmultisig only accept public keys with the old functionality
marked as deprecated.
Splits _createmultisig_redeemscript into two functions, one for
getting public keys from UniValue and one for getting addresses
from UniValue and then their respective public keys. The one for
retrieving address's public keys is located in rpcwallet.cpp
Adds a test to deprecated_rpc.py for testing the deprecation.
Update the tests to give only public keys to createmultisig.
Backport of Core PR11415
make VERBOSE=1 check && ./test/functional/test_runner.py
Reviewers: #bitcoin_abc, schancel, Fabien
Reviewed By: #bitcoin_abc, Fabien
Subscribers: Fabien, teamcity
Differential Revision: https://reviews.bitcoinabc.org/D2002