Add rotating banner of case study quotes and testimonials

Description
I would like to request adding a rotating banner of logos of case studies using knative project to the knative.dev site. This would be a great way to:

Showcase the success stories of people who have used the project
Provide social proof to potential users
Encourage more people to use the project

Proposed Solution
The rotating banner would be implemented as a simple carousel of images. The carousel would rotate automatically at a fixed interval.

Additional Information
Case studies are available in https://github.com/knative/docs/tree/main/docs/about/case-studies
Testimonials are available in https://github.com/knative/docs/blob/main/docs/about/testimonials.md