This reverts commit c0ccb808.

I am stupid and the CI can not use perf becaquse it is not installed.

This allows different stat files to be merged currently we have the
common stats file and the energy stats file. But we lose the guaranty
that all equal stat files actually share the same stats.

Also change the seperator used by perf from ',' to ';'.

* reduce allocations
  * allocate buffer on the stack
  * do not use buffered io
* do not convert []byte to string

This is a place to create and render plots.

* add implementation filter
* add format option for custom output
* add yaml output option

This matches the number of cores in a numa node on big03.

This is usefull when calling eval.py mutliple times from a script and
only some require root.
Always dropping privileges makes calling the script as root safer.