Moderation tool to delete comments in events/discussions

[spreeni]

The support team needs an option to delete comments within events or community discussions via the Couchers console.

[jesseallhands]

Related to #5122 which will enable users to report the content

[jesseallhands]

Right now we just have api.discussions.Discussions.CreateDiscussion, api.discussions.Discussions.GetDiscussion, api.threads.Threads.GetThread, and api.threads.Threads.PostReply

We need:

api.discussions.Discussions.DeleteDiscussion and api.threads.Threads.DeleteThread

For clarification, this is a discussion:

This is a Thread with a couple replies (Threads):

I believe Threads don't go any deeper than what is pictured above (so you can have a parent thread and child thread, but not a child of a child thread).