* Create S3 Third Party Test Task that Covers the S3 CLI Tool
* Adjust snapshot cli test tool tests to work with real S3
* Build adjustment
* Clean up repo path before testing
* Dedup the logic for asserting path contents by using the correct utility method here that somehow became unused
A tool to work with snapshots.
Co-authored by @original-brownbear.
This commit adds snapshot tool and the single command cleanup, that
cleans up orphaned files for S3.
Snapshot tool lives in x-pack/snapshot-tool.
(cherry picked from commit fc4aed44dd975d83229561090f957a95cc76b287)