E2 snapshot uploading

[mh0lt]

This change introduces additional processes to manage snapshot uploading for E2 snapshots:

erigon snapshots upload

The snapshots uploader command starts a version of erigon customized for uploading snapshot files to
a remote location.

It breaks the stage execution process after the senders stage and then uses the snapshot stage to send
uploaded headers, bodies and (in the case of polygon) bor spans and events to snapshot files. Because
this process avoids execution in run signifigantly faster than a standard erigon configuration.

The uploader uses rclone to send seedable (100K or 500K blocks) to a remote storage location specified
in the rclone config file.

The uploader is configured to minimize disk usage by doing the following:

• It removes snapshots once they are loaded
• It aggressively prunes the database once entities are transferred to snapshots

in addition to this it has the following performance related features:

• maximizes the workers allocated to snapshot processing to improve throughput
• Can be started from scratch by downloading the latest snapshots from the remote location to seed processing

snapshots command

Is a stand alone command for managing remote snapshots it has the following sub commands

• cmp - compare snapshots
• copy - copy snapshots
• verify - verify snapshots
• manifest - manage the manifest file in the root of remote snapshot locations
• torrent - manage snapshot torrent files