Feature request: Allow limiting snapshots

[mika-fischer]

Awesome tool!

However, we have a very large backup here where the data doesn't change much. It takes ages to sync the first time.

So to speed up the processing, it would be nice to be able to limit redu to the latest snapshot.

[drdo]

It might make sense to add a --last n option similar to restic's --keep-last to make redu consider only the last n snapshots.

[ilyagr]

I also am often interested in why the last snapshot was larger than I anticipated. Then, I often add some excludes, prune, and redo the last snapshot.

If redu supported --last 1, it would be very useful for this use-case.

[dionorgua]

It would be also cool to filter by hostname because different hosts may need completely different include/exclude patterns. Or different platforms at all