Bug 25744: replace <b> with <strong> in the staff interface

Bug 25744: replace <b> with <strong> in the staff interface

This patch set attempts to replace all the <i> tags with <em> and all
the <b> tags with <strong> in the staff interface.
I attempted to get all the templates, includes, and xslt files.

To test:

1. Review the changes as best as possible, looking for mistakes.
2. grep for <i> and <b> in the modules, includes, and xslt folders. You should get nothing/
3. If you grep '<\/i>' you should only see instances of Font Awesome.
4. If you grep '<\/b>' you should only see instances where caret is used.

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>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>