TPAC - set autofocus to user input when placing holds in staff client

When placing holds in TPAC via the staff client, the focus had been on the
basic search field above. Change this to have autofocus on the input field
for the hold user by default.

This can potentially save staff from having to perform an extra click to
select the input field. Now they can immediately begin entering the barcode
of the user they plan to create a hold on behalf of.

Signed-off-by: Ben Shum <bshum@biblio.org>
Signed-off-by: Mike Rylander <mrylander@gmail.com>