Admin to edit and add Spoiler

Subjects that don't need to be deleted but do need a spoiler and the member that posted either forgot the spoiler or didn't know.

For example, if a gif/picture was added that shows guns firing. Nothing necessarily bad about that but something that could trigger someone. 

We could delete it or we could track down the user to edit their post and add spoilers but it would be nice for the Mod's and Admins just to have the option to spoiler a members message rather than delete it.