[Docs] Update readme with plugin description

[leecalcote]

Current State

The readme doesn't specifically describe the helm plugin.

Desired State

Most or all of the Meshery content is replaced.

---

Contributor Guides and Handbook

• 📚 Instructions for contributing to documentation
  • Meshery documentation site and source
• 🛠 Meshery Build & Release Strategy
• 🎨 Wireframes and designs for Meshery UI in Figma (open invite)
• 🙋🏾🙋🏼 Questions: Discussion Forum and Community Slack

[welcome[bot]]

Thanks for opening this issue. A contributor will be by to give feedback soon. In the meantime, please review the Contributors' Welcome Guide, engage in the discussion forum, and be sure to join the community Slack.

[fitzergerald]

There's no activity here. I can do this.

[leecalcote]

Thanks, @fitzergerald