Retire app menu

Application menus have been a source of usability issues since they were introduced, despite attempts to improve them. We are therefore aiming to end their use by 3.32.0. Steps:

• The app menu should be replaced and a primary menu added in its place. This can contain all the existing app menu items.
• Rename the about item to "About Weather"
• Remove the Quit menu item

See the wiki page for design guidelines.