Bug 37553: Use CSRF token for authenicated session for POSTing

Bug 37553: Use CSRF token for authenicated session for POSTing

This change fixes the Koha::SVC to store the CSRF token for
the authenticated session for further POSTing.

Test plan:
0. Apply the patch
1. perl ./misc/migration_tools/koha-svc.pl \
    http://localhost:8081/cgi-bin/koha/svc koha koha 29 > bib-29.xml
2. perl ./misc/migration_tools/koha-svc.pl \
    http://localhost:8081/cgi-bin/koha/svc koha koha 29 bib-29.xml
3. Note that the following appears in STDOUT and there is no 403 error:
"update 29 from bib-29.xml"

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>