Reorder ci yaml reference doc

What does this MR do?

This MR is attempting to organize the massive ci reference doc into more logical groupings/orderings.

No content was edited, it was moved as-is. A few headers were slightly adjusted to match the topic better.

The biggest changes:

• Separate global parameters and regular (job-based) parameters into their own sections (since they work differently)
• Separate Variable-related parameters into their own section as well.
• Move related parameters to be next to each other
• Move some parameters higher on the list, for example:
  • rules higher than only/except, which is no longer recommended
• Nest a few parameters under "parent" parameters that they depend on, for example:
  • dependencies doesn't work without artifacts
  • services is related to images
• Move deprecations to the end.

TOC Before / After

(sorry for the size/color)

Related issues

#205397 (closed)

Author's checklist

• Follow the Documentation Guidelines and Style Guide.
• If applicable, update the permissions table.
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• Apply the documentation label.

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