Add internal constructors to prevent pointless initializations

Created by: armaa

Just like with the DiscordRole i PR'd earlier, being able to be initialized as a new object and making it useless, i checked the rest of the classes and i found more of it.. I am not sure about DiscordWebhook class and PropertyChange<T> in the DiscordAuditLogObjects class if they need it or not and i might have missed some too, so i would really like this to be double checked, just to be sure its all good