[ENG-193] Add menu item for opening Settings

[spacedrive-bot]

Add a menu item with a cmd-comma shortcut that navigates the active window to the app's settings.

_{maxichrome on Linear}

[spacedrive-bot]

I got blocked by the navigation on this and haven't had a chance to re-prioritize it. If another contributor / team member can peek at finishing client-side navigation — otherwise I'll get back on it when I can _{maxichrome on Linear}