Allows the user to create an object without file

Now the user can create an Object without providing an actual file
in the containers view. This will submit an object with 0 bytes size.
Additionally, the 'Download' button will not be available for objects
with 0 bytes size.

Implements: blueprint metadata-only-object
Change-Id: Ib2ff2462b73d16c971ad0dfc60aaae1b0bbf0924
Merge "Allows the user to create an object without file"