Bug 28170: Fix upload.tt search result buttons for page two onwards

Bug 28170: Fix upload.tt search result buttons for page two onwards

From https://datatables.net/faqs/index

"When attaching events to cells in a table controlled by DataTables, you need
to be careful how it is done. Because DataTables removes nodes from the DOM,
events applied with a static event listener might not be able to bind
themselves to all nodes in the table."

Before this patch, there were three non-functional buttons on upload search
result page, "+ Choose", "Download" and "Delete".

This patch binds the handlers to a static element so that the three buttons
in upload.tt on page two onwards are functional again.

To test:
1. This test is for the "Download" and "Delete" buttons
1.1. Before applying patch, go to cgi-bin/koha/tools/upload.pl
1.2. Make sure you have at least 21 files uploaded
1.3. Perform a search via "Search term" form so that at least 21 results are
     returned (e.g. a dot (.) as the search term should return all files with
     filetype)
1.4. Press "Download" and "Delete" for the first result row, it should work
     as expected (no need to actually delete the file - as long as it pops up
     a confirmation, it works as expected)
1.5. Go to page 2 of results
1.6. Press "Download" and "Delete" for the first result in page 2
1.7. Observe nothing happening
1.8. Apply patch
1.9. Repeat steps 3-6
1.10. Observe buttons working as expected

2. This test is for the "+ Choose" button
2.1. Go to cgi-bin/koha/admin/marc_subfields_structure.pl?op=add_form&tagfield=856&frameworkcode=#subufield
2.2. Under "Other options (choose one), for "Plugin", select "upload.pl"
2.3. Find a biblio and click Edit Record
2.4. Go to 856$u and click "Upload"
2.5. Repeat steps 1.1. - 1.10., but this time for the "+ Choose" button

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>