Add group-stage-category-change task list

Add the Group-Stage-Category-Change issue template with a list of things that need to be updated when making changes to a section, stages, group, or category. The list was compiled from various sources in Product#14293 (closed) and verified by numerous people.

The data README changes are to list the examples in alphabetical order. Otherwise, it adds a link to the handbook for more information on team tags.

Note: The gitlab-org/gitlab template does not exist yet. However, the content to be added can be currently found in the related issue description: Product#14293 (closed)

Corresponding handbook MR: gitlab-com/content-sites/handbook!15222 (merged)