Write to oplog on updates (with changes)

[sklirg]

I would like an oplog-entry when something is updated, not only added, like this: https://github.com/gathering/gondul/blob/dcf832a28b042687f1d0c742c0804c8eeb747df5/web/api/write/switches#L87

But not if there effectively are no changes.

Based on my understanding of the code it would require some "logic" to handle the previous criterion because currently, data is simply updated and no check is done on whether something changed.

This can be useful when data is synced into Gondul en-masse and there are many changes.

[KristianLyng]

I think this is doable, pretty sure we do an affected-detected thing, but you're right, it might need some logic. We'll look at it!