Redaction of non-officer faces in images

We need to get rid of non-officer faces in the images to protect the privacy of citizens. We should incorporate redaction into our tagging app by enabling people to flag citizen faces that should be blocked out. Once a sufficient number of tags from trustworthy users for a given face are present we can blank out that area in the image (this is to prevent officers from going in and blanking out officer faces). We'll preserve the raw hashes of images generated upon upload in #5.

Start by locating the tagging app flow and reviewing issue #5 for the raw image-hash requirement. Clarify how face tags identify citizens, how trustworthy-user agreement is measured, and where redacted images are generated. Done means the agreed threshold blanks qualifying citizen faces while preserving officer faces and the raw upload hashes.

Written by the indexing model from the issue text.