Create title screen(s)

Before the talk recordings and after them we need to display the sponsor logos from Platinum - Bronze sponsors. This is separate from the video sponsor loop that is used during breaks (cf. #10 (closed)) as this one is "a long, slow loop" (@stefanor) and the title screen(s) need to be ~5 seconds or so.

Examples from previous years:

1. DC19: Opening, Closing
2. DC18: Opening, Closing
3. DC17: Opening, Closing