Refactor Randomizer

[Serneum]

See @ericworkman's comment

• Rename randomizer
• Make the tests great again
• Refactor randomizer cause it ain't too pretty (and namespace it better)

In short, this randomizer uses the current year and day of year to as the index of the
list of availablegames to reliably choose the same game for a given day and game list.
I'm not happy with the tests, as I'm not too sure about how to set this up to be tested
reliably (but I barrelled through with it anyway). Paired with @Serneum while doing this.