[GNC] GnuCash repackaged for macOS

[John Ralls]

To fix https://bugs.gnucash.org/show_bug.cgi?id=799784, Gnucash loses focus after closing a reports options dialog.

Shasums:
26ae2e340edf2a58fdb906962cc48eb4ec1cf1a7b5862b72108f9a5401fd664b  Gnucash-Arm-5.16-3.dmg
f86d41e70a2d2124395baabc357124e1d04120039c741c18775473bd0deb3705  Gnucash-Intel-5.16-3.dmg

Downloads:
  * https://downloads.sourceforge.net/gnucash/gnucash%20%28stable%29/5.16/Gnucash-Arm-5.16-3.dmg
  * https://downloads.sourceforge.net/gnucash/gnucash%20%28stable%29/5.16/Gnucash-Intel-5.16-3.dmg
  * https://github.com/Gnucash/gnucash/releases/download/5.16/Gnucash-Arm-5.16-3.dmg
  * https://github.com/Gnucash/gnucash/releases/download/5.16/Gnucash-Intel-5.16-3.dmg

Regards,
John Ralls