Add notification option when creating new prayer requests

We've added an option to the new prayer request form that now gives users the choice of whether they'd like to send everyone an email notification for that prayer request.

Previously notifications were always sent (unless disabled in the prayer settings by an administrator), but this made it more difficult to add a bunch of existing prayer requests — like when first enabling this feature in Church Social — without sending the whole congregation a notification for every single prayer added.

Now users can simply select if they'd like to notify other members at the point of creating a new prayer request.