John Krasinski’s going to be busy for a while. Amazon has ordered up 10 episodes of “Tom Clancy’s Jack Ryan’’ starring the Newton native as the popular CIA hero previously played on the big screen by Alec Baldwin, Harrison Ford, Ben Affleck, and Chris Pine. The series, to be executive produced by director Michael Bay’s Platinum Dunes, Skydance Media, and Paramount TV, will be a prequel of sorts, with Krasinski playing Ryan as “an up-and-coming CIA analyst thrust into a dangerous field assignment for the first time.’’ It will not be based on a specific Clancy novel. The 36-year-old Krasinski, who’s best known for playing Jim on “The Office,’’ could use a hit. His last film, “13 Hours,’’ Bay’s movie about the attack on the American diplomatic compound in Benghazi, Libya, was a box-office bust. Krasinski also directed and stars in the upcoming “The Hollars,’’ a promising ensemble comedy-drama whose cast includes Richard Jenkins and Anna Kendrick.