[Feature]: Documentation Missing AI backends

[AnaisUrlichs]

Checklist

• I've searched for similar issues and couldn't find anything matching
• I've discussed this feature request in the K8sGPT Slack and got positive feedback

Is this feature request related to a problem?

Yes

Problem Description

The docs currently does not list all the AI backends that are available in K8sGPT:
https://docs.k8sgpt.ai/reference/providers/backend/

The following backends are missing:

cohere
amazonbedrock
amazonsagemaker
google
noopai

When you run k8sgpt auth list

Solution Description

If you want to document either of the missing backends, please create a PR (1 PR for each backend) and link to this issue.

Benefits

People would know what to do.

Potential Drawbacks

N/A

Additional Information

N/A