Bug 10861: (follow-up) various refactoring

Bug 10861: (follow-up) various refactoring

This patch refactors the previous code and moves the logic from the pl
to a new routine.

Same test plan as previous patch.

/!\ new unit test filename.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Bug 10861: Reintroduced the cardnumber length check (client side)

Previous patches has removed the pattern attribute of the input, it was
not needed. This patch reintroduces it. It will only work for new
browser version.

Moreover, it manages with the ',XX' format (see UT).

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Squashed the last two follow-ups. The pattern test did not work fully for me
in Firefox 26 (very recent). But I see the message when I clear the field.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>