Add OCI annotations to Dockerfile

[AlexGustafsson]

Description

Solve #24393.

Make the distributed docker image contain org.opencontainers.image.source label for easy reference back to this repository when the hashicorp/vault image gets updates. This is useful for tools like Renovate that makes updates to repositories when this image gets updates. OCI has standardized a few labels for adding metadata to images: https://github.com/opencontainers/image-spec/blob/main/annotations.md

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