update vi first step docs

[xyb994]

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Problem

vi first step docs are outdated

• github issue template
• clean up vi-team.md in Clean up the members pages #3181
• adapt newer content from mi first steps
  • mi-github-and-markdown.md -> vi-github-and-markdown.md
  • mi-github-and-repositories.md -> vi-github-and-repositories.md
  • mi-github-issues.md -> vi-github-issues.md
  • step 8
• update planet related content
• general cleanup

Screenshot (when necessary)

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Proposed solution(s)

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