Added client-side support for --contains-text on the list command.

- --contains-text with --installed or --consumed options use a
  client-side filtering implementation, where --available uses
  server-side.

- Fixed an issue which would cause output for --available or
  --consumed to be skipped if --installed or --available had
  zero objects to display.

- Updated the man pages and auto-complete accordingly.
See python-rhsm's certificate2.py, an EntitlementCert is a ProductCert with some extra data.