Rewrite ProcessResources collector

Features:
  * new metrics
  * performance improvements:
    - get full info only from processes that matched
    - get all info at once
    - do not reinitialize configuration
  * no support for blocking cpu_percent (causes gaps in graphs)
  * change the default path to /process

Known bugs:
  * tests do not work
  * no support for units because we have a lot of different metrics now