This PR:
- Implements safeguards for not accidentally/maliciously deleting repos
by sanitizing relative paths
- Adds versioning for snapshot schemas to allow invalidation if needed
- Adds logic to delete preexisting remote artifacts that might not have
been cleaned up properly if they conflict with an upload
- A bunch of tests for the changes here
Co-authored-by: Pieter Noordhuis <pieter.noordhuis@databricks.com>
shreyas-goenka