Bug 16963 - Remove the use of "onclick" from subscription add template

Bug 16963 - Remove the use of "onclick" from subscription add template

This patch removes the use of event attributes from the subscription add
template and the template for testing prediction patterns. Events are
now defined in the JavaScript.

To test, go to Serials -> New subscription.

- Test that the "Search for vendor," "Search for record," and "Create
  record" links work correctly.
- Test the "Next" button without entering a vendor or a biblionumber.
  You should be warned about selecting a vendor and biblionumber.
- After selecting a bibliographic record to link to the subscription,
  click the "Next" button. The second section of the subscription add
  form should be displayed.
- Under frequency, choose "1/day."
- Confirm that the "Show advanced pattern" link correctly toggles
  display of the advanced pattern form.
- Under the advanced pattern form, test the "Modify pattern" button. It
  should enable editing in the form.
- Test the "Cancel modifications" and "Save as new pattern" buttons.
- Test the "Test prediction pattern" button.
  - In the "Prediction pattern" box, test that the checkboxes next to
    each day of the week, when checked, trigger the corresponding issue
    number to be marked as "not published."
- Finally, confirm that your subscription is saved correctly.

Signed-off-by: Aleisha Amohia <aleishaamohia@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>