slapos_pdm: Remove "Software Catalog" feature since it was unused

   This is basically dead code, and untested.
5 jobs for fix/realtime-output-fix in 0 seconds
Status Job ID Name Coverage
  External
running SlapOS-Master.UnitTest-Master

28518:53:13

failed SlapOS.Eggs.UnitTest-Master.Python2

00:09:05

passed SlapOS.Eggs.UnitTest-Master.Python3

00:13:51

passed SlapOS.Eggs.UnitTest-Master.Python2

00:09:41

passed SlapOS.Eggs.UnitTest-Master.Python3

01:18:16