docs: consolidate firefighting manager role docs

Samuel Allanrequested to merge
samuel/ff-manager-2 into master

Description

In !678 (merged), we expanded the firefighting manager role. However, it turns out at some point this was already part of the role, and the info on firefighting managers was split across the roles page and the firefighting page.

Deduplicate the firefighting manager information into a single entry, and edit for consistency.

Supporting information

Private-ref: comment in private doc

Private-ref: https://tasks.opencraft.com/browse/BB-3149

Testing instructions

  • verify the changes render as expected and the links work
  • verify the information is accurate

Merge request reports