Bug 8566: [SIGNED-OFF] Enable koha-foreach to insert the instancename into commands

Bug 8566: [SIGNED-OFF] Enable koha-foreach to insert the instancename into commands

koha-foreach has been modified to replace __instancename__ with $name
on each iteration using sed.

The docbook file for koha-foreach has also been updated to reflect the
new functionality.

To test:

    koha-foreach ls -ld /etc/koha/sites/__instancename__

should list directories instead of giving an error message.

Signed-off-by: Magnus Enger <digitalutvikling@gmail.com>
The suggested example with ls works as expected, as does my
more complex example with fines.pl:

koha-foreach --enabled /usr/share/koha/bin/cronjobs/fines.pl \
--out /var/log/koha/__instancename__/

The man page looks good too.

Signed-off-by: Robin Sheat <robin@catalyst.net.nz>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>