3636 Account creation confirmation page should say wait 24 hours

https://code.google.com/p/otwarchive/issues/detail?id=3636

Was https://github.com/otwcode/otwarchive/pull/1438.

The following copy changes:
<i>In just a few minutes, you should receive an email at the address you gave us.</i> -> <b>Within 24 hours</b>, you should receive an email at the address you gave us.

<i>If you don't hear from us within 2 hours, and you don't find our email in your spam filter, please drop us a line...</i> -> If you don't hear from us within <b>24</b> hours, and you don't find our email in your spam filter, please drop us a line