Fix build without wallet and with Qt enabled

Summary: Move ToCurrentEncoding in guiutils and rename it convertToConfiguredAddressFormat for more clarity. It's current location is not compiled nor linked in when the wallet is disabled.

Test Plan:

../configure --disable-wallet
make check

Reviewers: #bitcoin_abc, schancel

Reviewed By: #bitcoin_abc, schancel

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1005