To specify scheduler hints options when create container,
this patch adds Scheduler Hints step into the creation dialog.
The Scheduler Hints step is not shown in update dialog.
For now, only Label Filter is available. So there are no
scheduler hint definitions in the left column.
Change-Id: I2eba1ac77deec797342fc1adff60f45e8ea0a70f
Implements: blueprint add-scheduler-hints-step