Add a nice screenshot/video of IAR to README

[rjw57]

We have a nice UI which is the selling point of the IAR and if we are to encourage others to follow our lead, we should treat the README like any other landing page and have a nice video and screenshot showing off our product. This is especially true since, at the moment, only a small subset of people can log into the the application.

Suggested by @uvimoran who was impressed by the IAR on his visit here.