Move the module from qemu_command.c to a new module virqemu.c and
rename the API to virQEMUBuildObjectCommandline.
This API will then be shareable with qemu-img and the need to build
a security object for luks support.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Unlike -device, qemu uses a JSON object to add backend "objects" via the
monitor rather than the string that would be passed on the commandline.
To be able to reuse code parts that configure backends for various
devices, this patch adds a helper that will allow generating the command
line representations from the JSON property object.
