Make assembly name mandatory during assembly creation

Currently it is optional. Submitting a create command
without a name makes a call to the API and fails at
the Solum API layer. Skipping mandaroty inputs should
fail at the CLI itself.

The usage docs will be updated using the following bug
https://bugs.launchpad.net/solum/+bug/1336348

Change-Id: I3710c0d2fc75337ea7e8c766417612a43810d7e8
Closes-Bug: #1332315
Merge "Make assembly name mandatory during assembly creation"