[electrum] build 64-bit windows binaries by default

Summary:
This adds support for 64-bit Windows releases, and makes it the default.

Required for qt6, and will help prevent MemoryError with large wallets.
32-bit Windows usage is now well under 1% of all running Windows computers.

The switch from wine makensis.exe (with a downloaded 32 bit makensis.exe) to the linux nsis package is a backport of electrum#8057

Test Plan:

contrib/build-wine/build.sh
wine dist/ElectrumABC-5.4.4.exe
contrib/make_clean

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D19530