Removing saving raw action/workflow result under 'task.taskName'

* If we always save raw task result under in the DB it causes problems
  if we, for example, have a huge raw result but don't need it all. We
  may just want to extract somethig from it like number of list items
  etc. E.g. array containing information about 30 VMs takes 130kb space
  and doesn't even fit  MySQL default text type.

  So if we need to save the entire raw result we can easily do that
  using:

    publish:
      full_result: $

  Or using any other key.

  This patch makes accessible the same variables defined in 'publish'
  via context key 'task.taskName'

Change-Id: I81af8496156afb3db46c016019880d84c12917ba