videos discord notification added

[ShadyNagy]

Closes #1134

CoachingSessionsNotifications must be in the settings.

"DiscordWebhookUrls": {
	"AdminUpdates": "(here)",
	"BookDiscussion": "(here)",
	"CoachingSessionsNotifications": "(here)",
	"DevBetterComNotifications": "(here)"
},

[ardalis]

Let's see if it works :)