Widget/shortcut should allow to sync

[Arthur-Milchior]

Let's say I've a single deck. I create a shortcut to the deck, or a widget that open the deck directly.
Then I never got an invitation to sync. I don't get an icon to invite to sync, nor a red or yellow label telling me syncing is needed, nor a regular reminder that no sync had occurred in quite some time. I assume all of you know this is how our users lose their data.

I think that the "sync" should be decoupled from the deck-picker so it can be reused elsewhere.
Then, when the reviewer is directly opened, when the deck picker is not on the stack, the sync option should appear in the reviewer.
Still, when the deck picker was used to open the reviewer, the sync button should not be present.

I guess the easiest way to do this is to pass a boolean in the bundle that indicates whether sync should be presented.

Contributors, note that this is only a suggestion. I want to get feedback from other maintainers without anyone start any implementation. If other maintainers agree this seems like a good idea, then we can start working on it