Like the unofficial marijuana holiday of 4/20, May the Fourth started as a fan event — in this case, a Star Wars-centric one — that has since been adopted by bars, restaurants, galleries and others as a way to drum up business. And, like 4/20, if you’re already deep into the subject matter, it’s a great excuse to indulge. Since Lucasfilm pulled the trigger on its plan to release a Star Wars film at least once a year — starting with 2015’s “The Force Awakens,” and continuing with last year’s “Rogue One” — the frenzy over all-things-Star Wars feels omnipresent.