WIP: Phase 1: #47282 Improving Contributor On-Boarding Documentation

What does this MR do?

This is part one for improving the contributor on-boarding documentation.

Are there points in the code the reviewer needs to double check?

• This needs to be reviewed by the relevant parties involved in #47282 (moved) before merging.
• All previous headings still exist in the contributing.md.
• No spelling mistakes are present.
• All hyperlinks are in a working condition.
• No content previously in the contributing.md is completely missing from the new locations.

Why was this MR needed?

To showcase the initial improvements to the contributor documentation

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

#47282 (moved)