Move last 5 docs out of the workflow dir

What does this MR do?

Moves the last 5 docs, as part of an effort to sunset the /workflow docs.

Source	Destination
workflow/shortcuts.md	user/shortcuts.md
workflow/time_tracking.md	user/project/time_tracking.md
workflow/timezone.md	administration/timezone.md
workflow/todos.md	user/todos.md
workflow/workflow.md	gitlab-basics/feature_branch_workflow.md

Related issues

Related to #32940 (closed)

Doc Move Workflow

• Move docs.
• Move images to correct /img for each doc.
• Update relative links within each doc.
• Update relative links to each doc from other docs (including /workflow/README.md).
• Make sure moved doc is linked from an appropriate higher level doc.
• Verify and move Disqus comments if needed.

Notes to reviewer

The content of these docs was not verified, reviewed, or edited in any way. The docs were moved "as is", and the only changes were to the links within the docs, and links TO these docs.

For review, please verify:

• The new location is correct / appropriate
• No content was lost when being moved.
• No links are broken as a result of this move.
• Disqus comments are properly redirected.

Author's checklist

• Follow the Documentation Guidelines and Style Guide.
• If applicable, update the permissions table.
• Link docs to and from the higher-level index page, plus other related docs where helpful.
• Apply the documentation label.

Review checklist

All reviewers can help ensure accuracy, clarity, completeness, and adherence to the Documentation Guidelines and Style Guide.

1. Primary Reviewer

• Review by a code reviewer or other selected colleague to confirm accuracy, clarity, and completeness. This can be skipped for minor fixes without substantive content changes.

2. Technical Writer

• Optional: Technical writer review. If not requested for this MR, must be scheduled post-merge. To request for this MR, assign the writer listed for the applicable DevOps stage.

3. Maintainer

1. Review by assigned maintainer, who can always request/require the above reviews. Maintainer's review can occur before or after a technical writer review.
2. Ensure a release milestone is set and that you merge the equivalent EE MR before the CE MR if both exist.
3. If there has not been a technical writer review, create an issue for one using the Doc Review template.