Add zip code search to !woppy to match Twitch bot functionality.

[portaljacker]

Currently the Twitch version of the !woppy command developed by Vaindil supports search by zip code, creating an expectation by new users on Crensloths coming from Twitch that Portalbot's !woppy command works the same.

Therefore the command should be updated to support, at the minimum, zip codes and Canadian postal codes. If an easy way to validate all postal codes exists then they can be accepted as well.