Add how-to guide for Flower's deployment readiness

[chongshenng]

Issue

Description

Our Flower deployment-readiness lack official feature documentation.

Related issues/PRs

N/A

Proposal

Explanation

Add a how-to guide highlighting the deployment-readiness feature of Flower.

Checklist

• [X] Implement proposed change
• ~~[ ] Write tests~~
• [X] Update documentation
• [X] Update the changelog entry below
• [ ] Make CI checks pass

Changelog entry

Any other comments?

N/A