Celsius's best growth days are probably over. Here is what investors should do now.Energy drink company Monster Beverage is an all-time great in the investing world; long-term investors have enjoyed life-changing returns, even if the stock was sometimes volatile. Investors are hoping that Celsius Holdings (CELH -0.86%), another energy drink business that has already appreciated more than 21,000% over the past decade, can still pump out big returns.However, the stock has fallen over 60% this year, causing in ...