Custom amount of result to include in the graph

The current implementation of the graph show last 50 test result, when the number of test is high and the progression is made on thousand of runs the graph doesn't show anything useful. (it's nearly flat)

Previous implementation (not using echarts) allowed the user to change the "from" value.

It would be a valuable addition to be able to show a graph for a higher amount of builds. (even if it's a fixed amount, like 50, 200, 500, 1000, all)