Make Settings its own menu about libtas

[clementgallet]

Upon use, this feels indeed less practical. Would you:

• keep the settings with tabs, and in the settings menu, points each menu item to the same settings window, with the associated tab opened?
• separate each settings tab in its own window, and points each menu item to this window?

[vadosnaprimer]

If it's possible to open the desired tab right away, having them all in the same dialog with tabs, individual menus opening their respective tabs, that'd be ideal. Dolphin works that way.