Add OakGate Technology specific configurations

This commit changes the returned version string to be compatible with
libvirt as well as puts the NVME and PCI configuration files in a
neutral location (/opt/nvmeqemu/config/). Neither change effects
functionality, but both help with the deployment of the emulator.

Signed-off-by: Chuck Tuffli <chuck.tuffli@oakgatetech.com>
Update status registers with shutdown status

Update the Shutdown Status (CSTS.SHST) field when the controller
receives a Shutdown Notification (CC.SHN).

Signed-off-by: Chuck Tuffli <chuck.tuffli@oakgatetech.com>