With so much of the Raiders’ offseason focus on new quarterback Fernando Mendoza , it’s easy to overlook how many changes and additions they made to their defense. Between the draft and free agency, they potentially added up to six new starters, completely overhauled their inside linebacker room and infused that side of the ball with youth and playmaking ability. The Raiders’ Maxx Crosby and his teammates are moving from a base 4-3 defense to a 3-4 this season. Getty Images A look at where things stand with the Raiders’ defensive depth chart, after free agency and draft: Defensive line Starters: DE Maxx Crosby, NT Adam Butler, DT Jonah Laulu Reserves: Thomas Booker, Tonka Hemingway, JJ Pegues, Brandon Cleveland, Brodric Martin, Treven Ma’ae, Laki Tasi, Gary Smith III The skinny: The Raiders are moving from a base 4-3 defense to a 3-4, so it will be interesting to monitor how it plays out in terms of who lines up where and who steps up at nose tackle.…