vfio/common: Move legacy VFIO backend code into separate container.c

Move all the code really dependent on the legacy VFIO container/group
into a separate file: container.c. What does remain in common.c is
the code related to VFIOAddressSpace, MemoryListeners, migration and
all other general operations.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
index 3746c9f..2a6912c 100644
--- a/hw/vfio/meson.build
+++ b/hw/vfio/meson.build
@@ -2,6 +2,7 @@
 vfio_ss.add(files(
   'helpers.c',
   'common.c',
+  'container.c',
   'spapr.c',
   'migration.c',
 ))