Use config files instead of cmd parameters

[Bernhard Haslhofer]

Since we probably have to deal with a variety of server settings, it makes sense to start the simulator by passing a JSON/YAML config file instead of cmd parameters. E.g.,

YAML

simulation: arxiv.org
no_resources: 700000
change_frequency: 2

inventory:

• type: sitemap
  static: true
  ...