Bug 8878 - a command to provide a shell with the koha environment

Bug 8878 - a command to provide a shell with the koha environment

This command behaves something like su(1), but provides you with a shell
as the koha user, and with the environment pointing to the right places.

Signed-off-by: Mason James <mtj@kohaaloha.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Liz Rea <liz@catalyst.net.nz>