vz: expand start/stop/... APIs for ACL checks

vz: expand start/stop/... APIs for ACL checks

  The original motivation is to expand API calls like start/stop etc so that
the ACL checks could be added. But this patch has its own befenits.

1. functions like prlsdkStart/Stop use common routine to wait for
job without domain lock. They become more self contained and do
not return intermediate PRL_RESULT.

2. vzDomainManagedSave do not update cache twice.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Signed-off-by: Maxim Nestratov <mnestratov@virtuozzo.com>