[artifactory] Add support for custom labels in the Nginx pods

[jiyeonmolloy]

PR Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] Chart Version bumped
• [x] CHANGELOG.md updated
• [x] Variables and other changes are documented in the README.md
• [x] Title of the PR starts with chart name (e.g. [artifactory])

What this PR does / why we need it:

Currently, custom labels (.Values.nginx.labels) are only added under metadata.labels! Therefore, added custom label support under template.metadata.labels as well, so the labels apply to the Nginx pods 🛩️ Please let us know if you have any questions!

Special notes for your reviewer:

Thank you for the review!

[github-actions[bot]]

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[jiyeonmolloy]

I have read the CLA Document and I hereby sign the CLA