Allow default coach change

It would be great if we had the ability to easily change the coach when doing a course/program/movement. Currently doing Sam's 90-day Hypertrophy Challenge, which are using the older coachs/videos, it would be nice to be able to check out the newer Coach Mike videos. Could be as simple as showing the coach dropdown under the 'Change Movement' button. Otherwise the more complicated option would be to set up a 'prefered' coach order in the settings, where you could rank/order all the coaches. Then the videos could be based on that order.