modules: Disable the Pivotal Tracker module

Change-Id: 65099216b8
Story-Id: SF-59
Update salsaflow.yml

Change-Id: a2d0d90855
Story-Id: SF-55
story open: Initial implementation

A new command - story open - is added as a part of this patch. It can
be used to open the issue tracker on the home page of the given story.

Change-Id: 99c459bb55
Story-Id: SF-55
Merge branch 'story/cmd-story-open' into develop