The Brooklyn Nets? Fugetaboutit. New York City’s largest borough is celebrating the growth of a convenience store chain it can call its very own. That’s because Bolla Management Corp. hasn’t just come of age over the past two years, it is setting standards in retail design and foodservice that are attracting the attention of customers and competitors alike.“We take our relationship with our customers very seriously,” said Harry Singh, president and CEO of family-owned Bolla Management Corp., which oversees the company’s retail, jobber, construction and consulting businesses.