Bug 28320: Add DB connection check to the SIP SC status message

Bug 28320: Add DB connection check to the SIP SC status message

This patch adds a lookup of the sip user during an SC status, confirming that
our DB ocnnection is working, and that our user is still valid

Additionally, it adds support for SC status to the sip_cli_emulator and adds basic
test coverage for the SC status message

To test:
1 - Apply patch
2 - Restart SP server
3 - perl misc/sip_cli_emulator.pl -a localhost -p 6001 -l CPL -m sc_status_request -su term1 -sp term1
4 - prove -v t/db_dependent/SIP/Message.t

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>