Hardcoded S3 details in integration with MinIO

[misohu]

Bug Description

To make make kserve integration with mlflow we are creating object-storage secret with annotations:

annotations:
     serving.kserve.io/s3-endpoint: "{{ s3_endpoint }}"
     serving.kserve.io/s3-usehttps: "{{ s3_usehttps }}"
     serving.kserve.io/s3-region: "{{ s3_region }}"
     serving.kserve.io/s3-useanoncredential: "{{s3_useanoncredential }}"

From these last three ones are not needed for integration with minio, but can't be committed in the secret (we will also need them in the future connecting to other object storage providers e.g. S3).

For now we keep them as constants in the src\charm.py file.

For its meaning refer to the upstream documentation .

Important finding. Kserve inference service will prefix the serving.kserve.io/s3-endpoint value with http:\\ or https:\\ based on value of serving.kserve.io/s3-usehttps.

To Reproduce

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Environment

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Relevant Log Output

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Additional Context

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