Disabling individual pings as channel-specific permission

This permission will allow staff to disable all pings in a channel. It would be helpful in moderating larger, especially competitive communities, where players tend to call each other out over wins/losses by pinging, in many cases leading to arguments and making the server less inviting for new users.

For example, this could be used as a temporary restriction if multiple users keep ignoring a 'respect others' rule. Similar to Slowmode, a little notification on the bottom could inform users that pings will not send out notifications in the channel. Role-specific pings would still stay active, e.g. in case someone needs assistance by moderators.