Elon Musk bought on Friday shares in Tesla worth about $1 billion, a regulatory filing showed on Monday, just over a week after Tesla’s board proposed an unheard of $1-trillion pay package for the Tesla CEO if the EV maker reaches major production, innovation, and market capitalization goals. Musk bought the Tesla shares indirectly through a revocable trust on Friday, a week after Tesla proposed “a super ambitious incentive package for a pioneering, ambitious and unique CEO”. This package could be worth about $1 trillion…