frontend: Select an empty profile does not work

There were the following issuse:
- the empty profile is represented by null but the ListModelTypeAheadListBox
  did not supported it. Fixed by adding the null as a supported value
- the null has been rendered by NullSafeSuggestBoxRenderer as an empty String
  but it was  nearly invisable in the editor. Fixed by adding a specific
  template for this case into the CommonApplicationTemplates
- the network name was not set (only the profile id). While the network
  name is depricated, it is still used by
  VmInterfaceManager.updateNicForBackwardCompatibility and expected to
  be set

Change-Id: I199d4ce14b55b3f552cf6138b7c3c5d21d620ccc
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1003609
Signed-off-by: Tomas Jelinek <tjelinek@redhat.com>