Mod proposals to Kroki post

According to earlier comment:

• try to reduce the hurdle for Gitlab non-natives using easier wording, some basic gitlab intro, link to actual gitlab examples.

To do:

• Easier intro text and links.
• Create Gitlab example project and link to it.
  • make that example public do this in parent branch kroki-post
• clarify post categories/types and show on front page ----> move to extra issue/MR

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