Custom deployment implementation

[richard-jones]

• PR: [when the PR is created, put a link to it here. DO NOT use the "linked PR" feature]
• User Test Scripts: [when there are user test scripts available link them here]

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Implement the appropriate Helm charts for deployment to Imperial Kubernetes clusters.

This issue is a placeholder, and may be closed and replaced with specific work items after Helm chart and Kubernetes issues have completed.

Acceptance Criteria

List the criteria which must be met for the issue to be considered complete

• A working deployment pipeline for Invenio v12 to Imperial Kubernetes cluster

[richard-jones]

Agreed in the meeting today to use Let's Encrypt for certs