Bug 20428: Add the option to specify a tmp uploads dir

Bug 20428: Add the option to specify a tmp uploads dir

This patch adds an option to the koha-conf.xml file for specifying
a temporary uploaded files directory.

The koha-create script is adjusted to handle it and a convenient option
switch is added. If ommited, it will default to
/var/lib/koha/<instance>/uploads_tmp.

koha-create-dirs is patched to create the required directory with the
right permissions.

The docs get the new parameter documented.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>