Improve annotation flagging

[zdavis]

We need to make a number of changes to how annotations are flagged. Let's do this as part of the OER work if there's budget for it.

• [ ] The "flag" label is unclear. Let's change it to "report abuse" or something similar (suggestions welcome).
• [ ] When a user flags an annotation, the user will be asked to select a reason: 1) this annotation contains objectionable content, or 2) this annotation is abusive or harmful or 3) this annotation is suspicious or spam
• [ ] We'll add a backend admin view that lists open flags for the instance.
• [ ] Each flag will have a detail view that shows the date flagged, who flagged it, the reason for the flagging, a link to view the flagged content on the frontend (if possible), and the content being flagged (eg, the annotation body). The detail view will give the user an option to "resolve" the flag or to delete the flagged content.
• [ ] Email notifications of flags will link to the backend view so the recipient can quickly resolve it.
• [ ] Expose flags scoped to a project on the project backend view (per #2924). This would allow project editors to resolve flagged, public annotations on their projects and help distribute moderation work.

[zdavis]

Thank you for taking the time to open this feature request. The Manifold team reviewed this issue during our bi-weekly meeting and the consensus is that this feature makes sense and is in keeping with our overall vision for the platform. Moreover, we see this request as a viable candidate for development under our current available funding. We’re adding an “accepted” label to this request to indicate that it’s within scope and possibly within budget.

The next step is for us to estimate the work involved with this and add it to our feature backlog. Our acceptance of the issue is not a promise that it will be implemented. We will balance this request against the other accepted requests and do our best to implement it within our current available funding.

This was an automated message, but please don't hesitate to reply. Our team watches these issues closely and will respond as soon as we're able to!

[zdavis]

Matt agrees to fund under OER work if possible.