[Feature]: Add explanation for filters

[rakshitgondwal]

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

Problem Description

Part of #46

Solution Description

Provide a proper explanation about the filters used in the K8sGPT CLI.
This should be added under the explanation section.

Additional Information

I am working on this.