Benchmark extensions: read input parameter from json, write and plot results

[agoscinski]

Possible extensions to the benchmark:

• [ ] python benchmarks in clang-9-debug take long (up to 4min30s), reduce python benchmark number of runs to 1 for circleci with an optional parameter
• [ ] benchmarking interpolator with another implementation
• [ ] benchmarking hyp1f1
• [ ] read benchmark related parameters from a json then no recompiling is needed for changed parameters and parameters can be changed in one spot for the python and c++ benchmarks
• [ ] plot benchmarks results and save as images
• [ ] a python benchmark library like pybenchmark or pytest-benchmark, which takes care of the timing of the functions and printing results