Create a mechanism to provide trigger or content warnings at both the resource and archival object level

The idea is to be able to more easily show/use text and possibly an additional visual indication when content at the resource and specific archival object level has material staff have decided may be disturbing to some users. If done, it would be good to extend this to other material record types in ArchivesSpace (accessions, digital objects, digital object components). This idea came up in the anti-racism and inclusion community discussions in summer 2020.