Alice Cooper is one of the musicians interviewed in “The History of Metal and Horror.” “Have you ever noticed how fans of metal, more often than not, are also fans of horror, and vice versa?” asks the host of “The History of Metal and Horror,” a documentary that will be available online, Feb. 18, as part of the spring 2022 edition of the New Jersey Film Festival. (Visit njfilmfest.com). Yes, as a matter of fact, I have. And “The History of Metal and Horror” explores that subject just as thoroughly as any 100-minute movie could. This is really, of course, a movie with two intertwined histories….