Add review permission

[Akhun-Delar]

It would be nice if I could give groups or users the permission to see reported content, not just admin-only.

This is probably relevant to bigger companies or organizations that have a person of trust. IT isn't that involved in those things.

[marc-farre]

In version 0.2.8 there was ManageReportContent permission which has been removed in newer version.
Perhaps we could put it back?