Let's start labeling our CHANGELOG entries

What does this MR do?

Adds the type attribute to a CHANGELOG entry. When you create a new entry the software asks for the category of the change and sets the associated type in type field of the file.

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

Why was this MR needed?

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
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #21949 (closed)