Projection and Classifier snapshots

[MerrionComputing]

To prevent having to run projections and classifiers from the beginning every time it should be possible to take "snapshots" as at a given sequence number and use these to seed any new request for a projection or snapshot to be run.

The snapshot should be stored as Blobs with the filename being some combination of projection name and sequence number.

[MerrionComputing]

I think a blob file with file name being e.g. snapshots/projection/{domain}/{entity}/{projection name}/{instance key}.{as of sequence number} would make the most sense as a naming standard?

(Then just have the content be the projection state as JSON)