knotty: show task progress bar

knotty: show task progress bar

In addition to the "currently running n tasks (x of y)" message, show a
progress bar for another view on how much of the build is left. We have
to take care to reset it when moving from the scenequeue to the
runqueue, and explicitly don't include an ETA since not all tasks take
equal time and thus it isn't possible to estimate the time remaining
with the information available.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>