Bug 9409: Add --dbhost parameter and dbhost field

Bug 9409: Add --dbhost parameter and dbhost field

This allows setting the remote db host correctly for
request-db either with a command-line or passwd file.

Signed-off-by: Lee Jamison <ldjamison@marywood.edu>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit e4573d709936bbd7f454a26f073e2131aa9c8df3)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit e4995e5196621f8d9aa76301af68064e39fdac6a)
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>