Bug 16286 - Use validation plugin when adding or editing patron category

Bug 16286 - Use validation plugin when adding or editing patron category

This patch updates the patron category entry form so that it is
validated using the staff client's globally-included form validation
plugin. This patch also moves the page's JavaScript into a separate
file.

To test, apply the patch and go to Administration -> Patron categories.

- Create a new category. Try to submit the form with the following
  fields empty:
  - Category code
  - Description
  - Both enrollment period fields
  - Category type
- Try to enter data in the category code field which contains characters
  other than letters, numbers, hyphens, or underscores.
- Try to enter non-numeric data in the following fields:
  - Enrollment period in months
  - Age required
  - Upper age limit
  - Enrollment fee
  - Hold fee
- Try to submit the form with both enrollment period fields filled.

Followed test plan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>