Add Frontend Architecture Process to Verify:PA

Why is this change being made?

As a team, we've run into a handful of speedbumps that I believe could be avoided with a more deliberate architecture process for our frontend. The intent for this process is to encourage planning ahead and asking for input in a way that supports our iteration value.

That means, the goal is not to create a perfect blueprint, but instead to document our goals, plan of attack, and reasoning so that we can get alignment and discover unknowns.

I expect this to be a process in iteration itself, so this is the first attempt.

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the "Maintained by" section in on the page being edited.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
  • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files. (this requirement has been removed pending identification of a new DRI for the handbook)