Fixes#6411
- fix the order of buttons and the Skip button transparent background
- don't let the subHeaderItem eat vertical space when it's not visible
- layout/margins/spacing/linespacing fixes
Fixes#6387
TLDR; since this is a GridView, it needs a width/height set and then
centered on top of the parent component (as opposed to `anchors.fill`)
Also added a scroll indicator in case the window height is not tall
enough and fixed some small warnings
The openPopup function was declared in AppMain
and used via dynamic scoping in many places in the
application. Moved function to Global component
and updated all places to call it via Global instead.
Closes#4267