core: introduce Base_addEditWorkflowComment helper script

This is intended to replace portal_workflow.doActionFor with edit_action,
which was only available for users with modify portal content permission
on the document and also is a bit low level.

It is a common, especially in project specific code that we use
edit_action to leave notes in history and provide better traceability
and we sometimes do this on documents where user does not have the
modify portal content permission.