This commit is a significant refresh of the Fedora DEI Team docs based
on our current best practices and team workflows, as described below:

Update attributes

This was the largest change made to the docs. Our attributes file was
updated, in response to feedback that the links to our Fedora Discussion
pages were broken after the recent change from #dei to #dei-team.
There was not advance notice made to the team about this change, so the
links are now broken and need to be updated so people are directed to
the correct place for our discussions.

While doing that, I pulled the template file from the Engineering and
Mindshare docs maintained in the Council docs repository to use as a
model. I updated our platforms from the template and then used the
attributes as much as possible throughout our docs. There is more work
to do, but in the future, this will make metadata updates easier. There
will only be one place to update URLs should they ever change in the
future.

Refresh index page

• Remove mention of podcast interview because the link is now offline.
• Change ticket tracker mentions from Pagure to GitLab.
• Drop mention of the mailing list and point to Fedora Discussion tag.
• Update information on where to find the team to just use Discourse and
  Matrix; we should try to funnel people to the places where the team is
  most active and connected to the rest of the Fedora community.
• Reframe the platforms on where to find us as "synchronous" and
  "asynchronous" instead of using platform names.

Refresh getting involved and meeting guide pages

• Used more xref's to external team documentation where applicable
  (e.g. Fedora Legal and Fedora Infrastructure).
• Update context of our communication platforms to not mention mailing
  list or Telegram group as primary ways to engage with the team.
• Drop Pagure in favor of GitLab for ticket-based task tracker.
• Fix formatting and minor flow improvements for explaining how to
  become a sponsored member of the DEI Team.
• Add social agreement and meeting format from the HackMD notepad.

Miscellaneous changes

• Per discussion with @mattdm and low-visibility users on Fedora
  Discussion, stop using punctuation marks to distinguish acronyms. This
  was originally done for the benefit of screen reader users, but this
  guidance is now out-of-date with how most screen readers work, based
  on community feedback.
• Change "Fedora Women's Day" to "Fedora Week of Diversity" where it was
  not already changed.
• Stop using :toc: attribute in pages, since the Fedora Docs theme now
  includes a table-of-contents in the sidebar by default.