chore: convert large PNG/JPEG images to WebP for #7247

[jothikaaravindhan]

Description

This PR addresses #7247 by reducing the size of overly large images (PNG/JPEG >1MB) in the src/ folder.
All images are converted to WebP with no visible quality loss:

• Graphics with text/logos → lossless WebP
• Photographs → high‑quality lossy WebP (-q 90)

Before/After sizes (selected examples):

Image	Original	WebP
cncf_hub_dashboard_mac.png	1.2 MB	140 KB
layer5-five-mascot-means-business.png	1.3 MB	852 KB
join-the-community.png	1.3 MB	~800 KB (lossless)

All references in MDX/JSX files have been updated to point to the .webp versions. The original large files are deleted.

Notes for Reviewers

• Animated GIFs were not touched (as per maintainer's note in the issue).
• Total size reduction: ~X MB (you can estimate if you want).

Signed commits

• Yes, I signed my commits.

[Rajesh-Nagarajan-11]

@jothikaaravindhan Please have a look why build is failing

[jothikaaravindhan]

@Rajesh-Nagarajan-11
I looked into the build failure. After pulling the latest changes, there were a lot of merge conflicts. I’m resolving them now and will push the updated code once everything is sorted. Thanks for your patience!

[jothikaaravindhan]

Closing this PR as it introduced build failures due to missed image reference updates during the PNG/JPEG → WebP conversion.

While working on optimizing large images, I converted multiple files but a few references (in MDX/YAML/GraphQL) were not fully updated, which resulted in build errors.
To address this properly, I’ve created a new PR with a cleaner and more focused set of changes, ensuring:

Image references are updated correctly
Build passes successfully (npm run build)
DCO sign-off is included

Please review the updated PR here: #7565

Thank you!