WIP issue-358 COPPA fix

Need to add validation and tidy things up. Also, maybe i should split all of this into a mixin?
There is a subtle bug here where if the `age <= CUTOFF_AGE.month`, but the `date > CUTOFF_AGE.date`, then the user is not allowed in. An example is if the user is `13 years + 1 month - 1 day old`, and month to month wrap around of the date does not occur.

Perhaps an easier approach is to convert the cutoff date to an integer, rounded to the nearest day. Convert the user input to a date, then to an integer, rounding to the nearest day. Compare the integers.

This will allow us to gracefully handle month to month and year to year date wrap around.

Or, we go spelunking for the old code that handled this.