Populate `kn plugins` page with existing `kn` plugins

[omerbensaadon]

Description:

We currently have a kn plugins page which is empty (https://dev-knative.netlify.app/development/client/kn-plugins/).

It would be nice if we could populate it with a table of the current plugins available to kn (found here: https://github.com/knative-sandbox?q=kn&type=&language=&sort=)

---

Story

As Daniela the Developer
I want to know what plugins are available for kn
So that I can better leverage the kn CLI

Acceptance Criteria

• See all available plugins

GIVEN I access client/kn-plugins/ 
WHEN I look below the first paragraph
THEN I see a table with all of the names of currently available plugins
AND THEN I see a link to the Github repo where the plugin is hosted

Sample md Table

kn Plugin	Description
[Plugin_name](Link to GH Repo)	...

---

Known Issues and Considerations:

https://github.com/knative-sandbox?q=kn&type=&language=&sort=

Who should probably pick up this issue?

• Existing Contributors
• New Contributors

[abrennan89]

I think we'd want eng folks to provide some input here wrt to the status of each of the plugin types and how ready they are to be included, maybe use those status badges that show the version / alpha etc on the pages covering these?

[abrennan89]

This seems to be a duplicate of #3534 - OK to close this one, @omerbensaadon ?