Create social advocates shadow program

Why is this change being made?

Per our Community Relations call today, I've created this MR to add a section to the Advocates handbook page to outline the purpose/desired outcomes of the shadow calls.

One of the outcomes I documented was that after the calls, the Advocates can work on documenting the 'path' that a response goes through as we make a judgement on if/how to respond. During the shadow calls, I suggest we pull some examples and general topics that call for each kind of action, and document these.

Perhaps we could create a workflow similar to the Education Workflow to show the various paths that a mention might go through, whether it be an advocate workflow or engagement from the social team.

@dplanella @wspillane @ksundberg @borivoje @LindsayOlson @ecook1

Does this MR meet the acceptance criteria?

Conformity

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