Bug 19778: Move template JavaScript to the footer: Serials, part 4

Bug 19778: Move template JavaScript to the footer: Serials, part 4

This patch modifies more and more staff client serials templates so
that JavaScript is included in the footer instead of the header.

This patch adds a new JavaScript include, showpredictionpattern.js,
which is used by subscription-add.tt and subscription-numberpatterns.tt.
it also adds subscription-add.js, moving most of the JS embedded in
subscription-add.tt into an external file.

To test, apply the patch and test the JavaScript-driven features of the
modified templates: All button controls, DataTables functionality, tabs,
etc.

 - Serials -> New subscription
   - Date pickers
   - Popup search windows for vendors and bibliographic
     records
   - Next / Previous buttons
   - Form validation
   - Prediction pattern operations

   Test with new subscriptions, editing existing subscriptions, and
   duplicating subscriptions.

 - Serials -> Manage Numbering Patterns
   - Datatable
   - Delete confirmation
   -> Edit
      - Datepicker, test pattern
 - Serials -> Manage frequencies
   - Delete confirmation
   -> Edit
      - Form validation
 - Serials -> Subscription details -> Planning tab
   -> Edit history
      -> Datepicker
 - Serials -> Subscription details -> Renew
   - Datepicker

Signed-off-by: Dominic Pichette <dominic@inlibro.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>