Multiple mosh pits, teenagers in blue face paint, and an endless supply of euphoric energy — these are all things that characterized the first of two sold-out Brockhampton shows at the Majestic Theatre. The self-proclaimed “greatest boy band since one direction” earned their title with a blowout performance on Sunday that ended up feeling like one of the best house parties I’ve ever been to, regardless if I was too old to be there or not.…