Use logarithmic scale for build result summary chart

Currently the click target is really small on the bars in the chart
when there is a big margin between the values of the individual results
(e.g. 100 Succeding Builds and 1 Failed Build).
Using a logarithmic scale on the y-axis balances the difference
on the bars in the chart.

In order to stay consistent with the ordering of the individual
build results types and to distinguish the click target a little
more I disabled stacking of the bars.

src/api/app/components/chart_component.html.haml

@@ -11,10 +11,10 @@
                       id: 'build-summary-chart',
                       width: '100%',
                       height: '300px',
-                      stacked: true,
+                      stacked: false,
                       responsive: true,
                       colors: ['#008000', '#DC3545', '#FFCC00', '#EEEEEE'],
-                      library: { scales: { y: { ticks: { stepSize: 1 }}}},
+                      library: { scales: { y: { ticks: { stepSize: 1 }, type: 'logarithmic' }}},
                     )
       :javascript
         linkBuildSummaryChartToBuildResultsTab();