By Reuters Staff (Adds detail on events, chairman move, background) Jan 6 (Reuters) - Events group Informa Plc on Wednesday forecast a more than 70% plunge in 2020 profit as the industry was ravaged by coronavirus-driven restrictions and halts in physical exhibitions worldwide. Hundreds of global events organised by Informa were cancelled or postponed last year due to the COVID-19 pandemic, denting a major chunk of revenue for the firm behind shows including China Beauty Expo, Monaco Yacht Show, World of Concrete and Arab Health. Mainland China resumed events since June last year, but several...