Clean up direction links

Why is this change being made?

We had a bunch of inconsistencies in our YML. This MR makes a few things consistent:

1. depts.yml is renamed to sections.yml
2. sections, stages, and categories have .direction links
3. remove https://about.gitlab.com from links

Note if this MR works, there should be no visible changes other than a few places where we say "Strategy" turning into "Direction".

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what