Suggest an alternate Qt installer for Windows builds (one with no signup required)

[tbttfox]

The suggested Qt installation step for Windows requires signing up for their website, and that's something I desperately try to avoid. And I know I'm not alone in that. A possible alternate option is aqtinstall, which makes installation even easier since it's just a couple lines in the command prompt.

I think this is what's required to replicate the steps in the windows build guide "Install Qt 5.15" section

pip install aqtinstall
aqt install-qt --outputdir c:\Qt windows desktop 5.15.2 win64_msvc2019_64
aqt install-tool --outputdir c:\Qt windows desktop tools_qtcreator
aqt install-tool --outputdir c:\Qt windows desktop tools_qtcreator_kits_and_debuggers

This even feels like something that could be added to the cmake configuration, maybe?