execution progress view (Version 2) - stacked

This is a variation of !1864 (merged) that uses a mixture of SVG and bootstrap's progress component to display several values in a single bar.

Stacking the bars is possible because the values have a fixed order (one is always bigger or equal than the other).

Semantically the bar is just an image. The legend contains all relevant information. I therefore did not even use aria-valuemax and similar on the bars.

It would not be strictly necessary to use the solution also for the first bar as it only contains a single value. However, mixing .progress and <meter> on a single page looked weird.