Bug 11805 - Use validation plugin when creating new basket in Acquisitions

Bug 11805 - Use validation plugin when creating new basket in Acquisitions

The page for adding a new basket in Acquisitions includes some custom
form validation JavaScript which can be removed in favor of HTML5
validation attributes and Koha's built-in validation plugin. This patch
does so.

To test, apply the patch and go to Acquisitions -> Choose a vendor ->
New basket. Try submitting the form without entering a basket name. This
should trigger a validation warning.

Submission of the form with valid data should work correctly. Editing an
existing basket should also work correctly.

Patch works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Works as expected, passes all tests and QA script.
Tried adding a new basket with/without basket name and editing
an existing basket editing/emptying the basket name.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>