Moderation features

[bates64]

• [ ] Be able to prevent users from doing various actions on the site, such as creating scratches, forking scratches, saving changes to a scratch, decompiling, or compiling a scratch
• [ ] Be able to apply said restrictions by user, profile, and/or ip
• [x] Admins should be able to delete any scratch from the main ui
• [ ] Admins should be able to perform cleanup of unclaimed scratches that are more than x days old

Related to #299