[Suggestion] Mark channels as "Bot Only"

The idea of this is a backwards compatible way for bots to know the channel they want to send a message in is similar to a #general channel, and should convert reactions to a command to ephemeral, but without actually blocking the bot from doing stuff. This mark will only be used by the bot itself in his development area ( for his API ) and nothing else, and could contribute greatly to not having to scroll endlessly to find #bot-commands, while remaining a non intrusive solution for the bot developer.