“I say we trust until we don’t.” Richard Cabral’s character utters that phrase about 2/3 of the way into tonight’s sprawling premiere (the first episode runs 1 hr, 8 minutes without commercials) of Elgin James and Kurt Sutter’s latest chapter in the SoCal motorcycle club epic, MAYANS M.C.   As Sutter has mentioned in interviews, the show is set in a post-Jax-Teller-post-SAMCRO world, and the line above about trusting who you need to in the moment, until you might not trust