2023 docs refresh: Update metadata, links, & meeting information
    
    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.
    
    Signed-off-by: Justin W. Flory (he/him) <jwf@redhat.com>