knowledge: PEP8 and PEP257 improvements

* Removes `__init__` methods.  (PR #2184)

Co-authored-by: Javier Martin Montull <javier.martin.montull@cern.ch>
Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
workflows: passed data check

* Adds a check that passed data to the workflows API is indeed
  a list.

Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
workflows: wrong default position

* Fixes the default position of workflows when restarting a
  workflow. closes #2177

Reported-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>