For #54140547, Canifying the people and documents lists.

This commit creates new templating for people and references, using the ListViewController.  Also, the modal selector controller has been slightly modified to allow the existing list of people and documents to be used when mapping.  This introduces a bug wherein all of the checkboxes disappear from mapping after mapping or unmapping the first person or reference.  Will file in Pivotal as soon as this PR is merged.

Also added in the work for #55131502 which somewhat builds on the ready availability of people linkages from this PR