Implement an app settings panel

[luizf-lf]

The app currently does not have a settings panel, which itself is base feature needed to allow custom user configuration for the app, such as, but not limited to:

• App logs visualization, cleaning and rotation configurations.
• Extended dark mode configuration.
• Extended language configuration.
• Kiosk mode timing configuration (#15).
• Update manager (#14).

And many other features to come.

It may be a good idea to implement the setting panel as a new window, instead of an app component rendered by the main router.