Bug 20803: Cannot search to hold or use print options from API keys interface

Bug 20803: Cannot search to hold or use print options from API keys interface

This patch adds a required JS asset to the patron API key interface.
Without it, JS-based functions in the toolbar do not work.

To test you must have RESTOAuth2ClientCredentials enabled.

 - From a patron detail page, choose More -> Manage API keys.
 - Test the toolbar buttons on this page, especially "Search to hold"
   and the various print options.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>