Explore storing checksum of bundles in the dataset object to reduce computation

Created by: deepakduggirala

bundle means either tar, tar + zip, tar + zip + enc of the dataset directory.

In archive step, after making the bundle to upload to SDA, save the checksum to the database

This will be useful to avoid computing the checksum of local bundle file, provided that only the application has write permissions on the location of these bundles.

Try storing the file metadata (mtime, size) for a quick check?