HTML report: Improve performances of generation for big JTL files

[asfimport]

@pmouawad (Bug 65892): The time taken to generate the report increases importantly for big files.

For example for a file of 37 Gb, it takes 30 minutes to 1 hour to generate the report on an average VM.

Ideas:

• Parallelization seems to be necessary to improve that.
• Switching from commons-maths DescriptiveStatistics to HDR Histogram for percentiles calculation might be also a way to improve that.

OS: All

[asfimport]

@FSchumacher (migrated from Bugzilla): Have you done some profiling, to see where we spent our precious CPU cycles?

The HdrHistogram would be nice, if we would resurrect the patch for the GUI listener work, that used it.