Rename virCgroupForXXX to virCgroupNewXXX

Rename virCgroupForXXX to virCgroupNewXXX

Rename all the virCgroupForXXX methods to use the form
virCgroupNewXXX since they are all constructors. Also
make sure the output parameter is the last one in the
list, and annotate all pointers as non-null. Fix up
all callers, and make sure they use true/false not 0/1
for the boolean parameters

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>