Bug 35444: Add hidden span with information about the loggedinuser categorycode

Bug 35444: Add hidden span with information about the loggedinuser categorycode

To test:
1. APPLY PATCH
2. Log into the staff interface and use the browser's dev tools to look
   for the HTML class 'loggedincategorycode'. It should match the
   current logged in user's categorycode.
3. You could also use a console.log like so:

console.log( $('.loggedincategorycode').text() );

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 4a4032745293af7a3fec97c44c61b11c94e0edf7)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>