Add Helm chart for rclone as an S3 encryption proxy

[mikeshootzz]

What this PR does / why we need it

This adds a Helm chart for deploying rclone as an intermediate S3 encryption proxy. The chart configures rclone to:

• Accept S3 API requests
• Encrypt files and directory names using rclone's crypt functionality
• Store encrypted data in a backend S3 bucket
• Configurable security contexts for pod and container
• Backend S3 credentials managed via secret references
• Encryption passwords stored in separate secrets
• Resource requests and limits with sensible defaults

Checklist

• Chart Version bumped
• I have run make docs
• Variables are documented in the values.yaml using the format required by Helm-Docs
• PR contains the label that identifies the chart, e.g. chart/<chart-name>
• PR contains the label that identifies the type of change, which is one of
  [ bug, enhancement, documentation, change, breaking, dependency ]