About: Use Qt.createComponent to create About Page

This MR uses Qt.createComponent to create the About Page. This works for Widescreen and Mobile configurations. Using this component removes manual logic for maintaining this and instead allows us to use a Kirigami-Addons component available since v1.1.0 that will automatically create the page and pull in the About Page data (unsure if any files need updated to denote this requirement, let me know if I missed something please!)

This should result in no visual changes from master.

Before

Widescreen (shows as separate dialog box in Settings menu)

Mobile (shows in single window)

After (This MR)

Widescreen

Mobile

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Apologies if this change is undesired, although it does seem like applications are porting to use this. All feedback is welcome if I missed something or did anything wrong. 🙂

Thanks!