Four stars. Rated PG. 83 minutes. The movies have given us lots of reasons to feel exhilarated this summer, from the pop-feminist stylings of Gal Gadot in “Wonder Woman” to the goofy ensemble kick-in-the-pants that is “Girls Trip.” And now we have “Step,” a soaring, heart-bursting portrait of a group of intrepid Baltimore high school students guaranteed to bring audiences to their feet – whether out of vicarious triumph, overpowering pure emotion, or simply to pay tribute to the superheroines at the core of its infectiously inspiring story. When filmmaker Amanda Lipitz began following the story, in 2009, her intention was to record the first year of the Baltimore Leadership School for Young Women, an all-female charter school Lipitz had helped found.