I f you’re Julieta Venegas — the beloved, accordion-playing folk-pop dreamer who blazed a distinct musical trail in Latin indie-rock with open-hearted elegies that have sold millions and millions of records since the early 2000s — laying out your complex life story might seem like a daunting task. Yet for a long time now, the Mexican singer-songwriter had been kicking around ideas for a project that would let her reflect on her decades-long career and upbringing, linking together chapters like her childhood on the border and her early days playing in bands like the ska outfit Tijuana No! Maybe a memoir? Maybe an album?  Or maybe both. This month, Venegas is unveiling two massive endeavors she’s poured everything into over the last few years: One is the newly released book Norteña: Memorias del Comienzo , a personal history that looks at what led to her career in music. Then there’s the companion album Norteña , out on May 14, which plays like an audio version of her exercise in reflection and nostalgia.…