Elon Musk unveiled his “master plan” for Tesla Motors Inc., delivering a long-term vision that includes making an integrated solar and battery storage system and building a freight truck and a bus. He even has a plan for a ride-sharing business. Musk delivered the long-awaited plan on the company’s website to explain why the integration of Tesla and SolarCity Corp. is necessary and to show his vision for the two companies. He wants to use…