[request] Enable support for backblaze

[MayurDuduka]

Please describe problem to be solved
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• https://www.backblaze.com/

[sarahwooders]

@MayurDuduka thanks for the suggestion! We are currently working on adding support for generic S3 endpoints in #800, so we should be able to add Blackblaze support once that is done. Would you be interested in contributing the integration?