Add support for building Qt locales with cmake

Summary: This is a first step toward being able to build bitcoin-qt with cmake.

Test Plan:

ninja bitcoin-qt-base

Reviewers: #bitcoin_abc, jasonbcox, schancel

Reviewed By: #bitcoin_abc, jasonbcox, schancel

Subscribers: jasonbcox, teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1083