[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.

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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]

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.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.