Fix the " error demultiplexing archive" error during restore by downloading backup from s3 storage in chunks

There is reported issue while during the restore from S3 pbm fails with

[ERROR] restore/2020-09-07T10:54:20Z: restore: restore mongo dump (successes: 26676221 / fails: 0): BetaProcessing.email_log: error restoring from archive on stdin: reading bson input: error demultiplexing archive; archive io error

 And on different restores it might happened to different collections.

Basically error happens when `mongorestore` util fails to read the file from the remote store due to network/IO issues.

Can we do something on our side to make PBM resilient to this error?