Evolv Technology, a 7-year-old maker of sensors and software aimed at detecting weapons or other threats concealed on people, is adding another high-profile investor as its CEO switches to a more technical role within the company. The Waltham-based company announced on Wednesday $30 million in a new funding round led by former Florida Governor Jeb Bush’s firm, Finback Investment Partners. Microsoft (Nasdaq: MSFT) Co-Founder Bill Gates, is a returning investor in the Series C round. “Jeb and his group fully understood the opportunity here,” said Peter George, the company’s newly-promoted CEO. “As the former governor in Florida, where there have...