Eio backend for console

Runs console's progress rows with Eio. It finds whether the output is a terminal and its size, redraws the rows, shows the program's output and its Logs messages under the task that printed them, and gives the terminal back when the run ends, when the program exits and on SIGINT or SIGTERM. On a pipe or in CI each task prints lines instead, or JSON events on request. It also asks for a line, a yes or no or a password on the terminal, and reads keys as they are typed.