Deleting messages doesn't require the client's permissions to be superior to the author of the message

[metagn]

If the title wasn't clear enough, DiscordUtils' checkPermissions method seems to check the client's permissions be equal to the permissions given. Thing is, deleting messages doesn't require this and only the client to have sufficient permissions to delete the message. Therefore, that method wouldn't exactly work.

P.S.: You seem to also check for mentioning everyone and embedding permissions, even though the client should still be able to send that message with everyone and embedding and without permissions.