Use GetKeyForDestination in various RPCs

Summary:
This backports elements of Core PR11403:

• Support P2WPKH addresses in create/addmultisig : https://github.com/bitcoin/bitcoin/pull/11403/commits/37c03d3e05713e14458ca2867e442926f165afea
• Support P2WPKH and P2SH-P2WPKH in dumpprivkey : https://github.com/bitcoin/bitcoin/pull/11403/commits/cf2c0b6f5cde584d7004ff1b5b476ef54de6b74b

Test Plan:

make check
./test/functional/test_runner.py

Reviewers: #bitcoin_abc, markblundeberg

Reviewed By: #bitcoin_abc, markblundeberg

Subscribers: markblundeberg

Differential Revision: https://reviews.bitcoinabc.org/D3131