S3 source should work for non-AWS S3 storages

[Phlair]

Currently S3 source is tied to AWS S3 (with url strings etc.). Should be relatively straightforward to extend this to support other storage systems following S3 protocol.

[sherifnada]

@Phlair what's an example of this? Minio? Any examples you add would help make this a reality :D

[Phlair]

Some examples:

• MinIO
• Ceph
• LeoFS
• Wasabi

The ideal soultion would be provider agnostic, such that the code uses boto3 to handle s3 compatible storage systems in a single generic approach, rather than cases for each S3 provider and setting in spec. The generic approach would then just use a user-provided base url along with access and secret keys to hit the relevant storage (AWS could be default for base url perhaps)