Add support for report-level tagging by SMTC monitors #333
Description
From @limmabean on Trello:
Post-Level tagging is only done automatically by the backend. So essentially, the only way to manually label posts or to give them extra qualities besides flagging them is to group them into incidents. The title of that incident then becomes the extra label. However, due to the way we define incidents, we also want to manually provide post-level tag e.g. "actionable hate speech" or "sexism". Posts labeled like this may not be in the same incident, but have those tag qualities regardless. This will be helpful for data analysis or simply identify posts that don't necessarily fall into an incident grouping.