A new play running in Boston focuses on what outsiders might consider an unlikely profession when it comes to the creation of dramatic sparks: art authentication. Of course, the play isn’t exactly an accurate depiction of the authetication business, any more than architects’ lives resemble that of Indiana Jones, but the production does call attention to a little-known, but vitally important, corner of the art world, and sheds some light on the rivalries and internal politics that can affect it.