Bug 26330: Change encoding of text used as tab triggers in MARC subfield constraints

Bug 26330: Change encoding of text used as tab triggers in MARC subfield constraints

This patch changes the encoding of the data being used to define
jQueryUI tabs on the MARC subfield constraints page. A jQueryUI bug
prevents non-Latin-1 characters from being used when defining tab
controls. Using Template:Toolkit's "uri" filter converts the data to
usable characters.

To test, apply the patch and go to Administration -> MARC frameworks ->
MARC structure -> tag 952 -> Edit subfields.

- Under the "New" tab, add a subfield code which is outside the basic
  Latin character set, e.g. £, §, æ.
- Save changes.
- Edit any subfield code to load the subfield constraints page again.
- Test that the subfield code tabs work correctly: Clicking each tab
  should load only the corresponding panel.
- Test a variety of tabs including the one you created with the
  non-Latin character.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>