Delete tb-crashes role
The tb-crashes role was created in #22923 (moved) for creating a pair of (mini-breakpad) servers where crash reports would be sent and viewed. That server was decommissioned in #31095 (moved). Although #23624 (moved) is still open, and this would be a really nice improvement, I don't see us getting back to this in the near future.
I think we should delete the tb-crashes role for now, and we can recreate it in the future if/when we get back to this.