add Meshery playground, helm-kanvas-snapshot plugin, kanvas and tutorials.

[vishalvivekm]

Review the Contributing Guidelines

• [X] Before submitting a pull request, verify it meets all requirements in the Contributing Guidelines.

Describe Why This Is Awesome

• Kanvas Snapshot Helm Plugin allows users to generate a visual snapshot of their Helm charts directly from the command line, providing a visual representation of packaged Helm charts.
• Meshery Playground aka CNCF playground lets anyone learn about all 150+ CNCF projects.

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