Adding collector_args

[alexandraBara]

Adding collector args to customize data collection through cmd line/config args.
Currently only ProcessPlugin has them. Sample run:

node-scraper --gen-reference-config run-plugins ProcessPlugin

sample reference_config.json:

{
  "global_args": {},
  "plugins": {
    "ProcessPlugin": {
      "analysis_args": {
        "max_kfd_processes": 0,
        "max_cpu_usage": 0.20000000000000284
      },
      "collector_args": {
        "top_n_process": 0
      }
    }
  },
  "result_collators": {}