[Development] Proposing a wiki page for Qt6 buildsystem requirements

[Bogdan Vatra]

Hi,

  I'd like to propose a new wiki page (https://wiki.qt.io/Qt6/Requirements ?) 
where, at least all platform maintainers, will add all the features they need 
for that platform.
  As the Android maintainer I'm not happy with current qmake support, not to 
mention cmake support which in this moment is behind qmake.

Cheers,
BogDan.