Adoption of `RunnerConfig` with a optional `transform` function.

[BioPhoton]

If a transform function is provided,
the output of a plugin is piped through the provided transform function after we read the plugin-output.josn.

{
  plugins: [
    {
      outputPath: "out.json",
      transform: (data: Record<string, any>): PluginOutput => {
          return {
            //...
          }
      }
    }
  ]
}

related to #92