Create a new revlog entry for "Reschedule cards on change"

[user1823]

Currently, the revlog entry for "Reschedule cards on change" is the same as that for "Set Due Date". This is the cause of several issues, including

• Assigned memory state after 'set due date'+optimize incorrect #2998
• [Feature Request] Manually set due dates should not get overwritten by resheduling of load balancer open-spaced-repetition/fsrs4anki-helper#442
• Exclude manual entries from remote reviews open-spaced-repetition/fsrs4anki-helper#434

There must be other issues too that I am not remembering.

The solution is to use a separate revlog entry to distinguish "Reschedule cards on change" and "Set Due Date".

The first step is to decide the column in the revlog table whose value can be changed while minimizing add-on breakage (they may be making assumptions about the possible values).
Possible options: type, ease, factor

IMO, type is the only column where a change would appear to be "logically" correct. However, I am not sure if using type = 5 for "Reschedule cards on change" would lead to significant add-on breakage.

[brishtibheja]

I assume it has to be an +ve integer number?

[dae]

Type=5 is the most logical. I'm not too concerned about add-ons as we've added '4' in the past too, but it will require going through the Anki codebase to make sure we handle that case in all the graphs/stats.

[brishtibheja]

I assume the search prop:resched will still work for us users? That's sometimes useful.

[dae]

If it is useful to distinguish them in a search, we might want to add a new search term?