Correct channel settings and all role permissions

[snapcat]

• Correct verified role permissions
• Correct unverified role permissions #16
• Correct instructor role permissions
• Correct settings for q-and-a channel
• Correct settings for instructor-commands channel

Verified users are given general server permissions. This includes:

managing roles
viewing audit logs
server management

Which shouldn't be the case.

The instructor role is also placed lower than the verified role, meaning the user has to manually order them.