Bug 20568: (follow-up) Interface and markup changes

Bug 20568: (follow-up) Interface and markup changes

This patch makes some interface changes to bring things better in line
with existing interface patterns. This patch also re-indents the
modified templates with 4 spaces instead of 2 and makes <input>s
self-closing.

Also changed: Corrected system preference check in opac-apikeys.pl.

To test, apply the patch and:

In the staff client:

 - Open a patron record and choose More -> Manage API keys.
   - There should be a standard message dialog containing a link to
     "Generate a new key."
     - Clicking the link should show the form for adding a new key.
     - Test that clicking the "Cancel" link hides the form.
     - Test that creating the new key works correctly.
   - You should now see a table showing existing keys and a "Generate a
     new key" button above it.
     - Test that the "Delete" button asks for confirmation, and that
       confirming and denying both work correctly.
     - Test that "Revoke" and "Activate" actions still work correctly.

In the OPAC:

 - Set the AllowPatronsManageAPIKeysInOPAC system preference to "Allow."
 - Log in to the OPAC and click the "your API keys" link in the sidebar.
   - Clicking the "Generate new key" button should display the form for
     adding a new key.
     - Clicking the "cancel" link should hide the form.
     - Submitting the form should add a new key.
   - You should now see a table showing existing keys.
     - Test that the "Delete" link asks for confirmation, and that
       confirming and denying both work correctly.
     - Test that "Revoke" and "Activate" actions still work correctly.
 - Set the AllowPatronsManageAPIKeysInOPAC system preference to "Don't
   allow."
   - Log in to the OPAC and confirm that the "your API keys" link in the
     sidebar is no longer visible.
     - Confirm that navigating directly to /cgi-bin/koha/opac-apikeys.pl
       results in a 404 error.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>