settings.production: Allow extra azure configuration

Currently, the writing in the azure objstorage adds extra headers to the blobs. Which prevents the correct reading of those blobs when checking the tarballs.

According to the documentation, this option opening should allow to configure more appropriately.

Refs. swh/infra/sysadm-environment#5129 (closed)

mentioned in merge request swh/infra/ci-cd/swh-charts!238 (merged)

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mentioned in issue swh/infra/sysadm-environment#5129 (closed)

merged