Revert "Improve readability of old settings on mac"

This reverts commit 76fa038787bbfd2f2b3844ab63b7bb5a443e4f6e.
Revert "Fix settings display on macs"

This reverts commit 96ecd539de8e76a880f0013b4b8854da216e17b1.
Tidy up mythwidgets; and add MythLabel and MythGroupBox.

While I reverted 96ecd539de8e76a880f0013b4b8854da216e17b1, the code structure was much better that way
Replace all QLabel and QGroupBox with MythLabel and MythGroupBox respectively
Fix settings display on macs

My analysis for the problem in 96ecd539de8e76a880f0013b4b8854da216e17b1 was wrong.
The actual issue is that QPalette inheritance appears broken on a mac; if you set the palette to the top widget container, it doesn’t do anything on its children. However, setting the palette to the main application itself does.

Now things look exactly the same between mac and linux for better or worse. Including font sizes and colors.
A downside, is that the selection color appears to be misused in most themes including the default. So you can't tell if a text is selected or simply having focus