Meme: Removable bot reactions

[sinus-x]

When the uwu or randomcase commands are invoked, the message ID should be saved to internal cog cache, as dictionary key with user ID as its value. A ❎ should be added as a reaction to the new message.

When the author clicks the reaction, the message should be deleted. If someone else clicks it, the reaction should be removed.

This functionality should have some cooldown -- a timer would go every ten minutes through the reactions and if they were older than ten minutes, it would remove the reaction (?) and delete the message from the cache.