Allow moderator, or other role, to delete review comments

From gbonehead:

We'd like to use Crucible for collaborative code reviews, but find it to be really really awkward. The problem is that we have a group of N people all entering comments, and when the review is complete most of them should be modified or deleted - yet only the author of the comment can modify it.

The moderator should really be able to edit and/or delete any comment in a review - after all, they ARE the moderator - which would help a finalized review actually have useful information rather than a bunch of stream of consciousness commentary of unknown and potentially dubious value.

Does anyone know how to set up permissions for Crucible so a single person can unify and clean up the comments?

See https://confluence.atlassian.com/display/CRUCIBLE/Adding+comments?focusedCommentId=370704730#comment-370704730