Add options to revert/undo in the Settings Menu

[amalnanavati]

(Not an MVP feature; we shouldn't focus on this at the moment)

As mentioned here, users may make a change in settings and then either want to undo that change or revert to the default altogether. Therefore, this issue is to add those buttons, either for the whole settings page or per-setting.

However, I imagine users wanting to revert will be particularly important for complex settings, like customizing the staging location in a continuous space. I think the few settings we have as of now should be easy enough for the user to remember, hence I don't think this feature is imminently necessary.