Add export_parameters to metadata.json in export archives

[CasperWA]

Closes #3360

Current "data structure":

{
  "export_parameters": {
    "link_follow_rules": {
      // Updated dict from config.LINK_FLAGS
    },
    "original_entities": {
      "Node": [
        // UUIDs of originally chosen Nodes that should be exported
      ],
      // Possibly also "Computer": [] and "Group": [].
      // "Node": [] May also be left out, if no Nodes were specified to be exported.
    },
    "licence_info": {
      "allowed_licenses": null, // or a list or, if the parameter was a function, a string, naming the function that was used
      "forbidden_licenses": null // same as for "allowed_licenses"
    },
    "include_comments": true, // reflects the boolean parameter of the same name
    "include_logs": true // reflects the boolean parameter of the same name
  }
}

Example, which is also added to the docs:

{
  "export_parameters": {
    "link_follow_rules": {
      "input_calc_forward': False,
      "input_calc_backward': True,
      "create_forward': True,
      "create_backward': True,
      "return_forward': True,
      "return_backward': False,
      "input_work_forward': False,
      "input_work_backward': True,
      "call_calc_forward': True,
      "call_calc_backward': False,
      "call_work_forward': True,
      "call_work_backward': False
    },
    "original_entities": {
      "Node": ["1024e35e-166b-4104-95f6-c1706df4ce15"]
    },
    "license_info": {
      "allowed_licenses": None,
      "forbidden_licenses": "Function valid_licenses was used to check for forbidden licenses"
    },
    "include_comments": True,
    "include_logs": False
  },
  // ...
}  

[CasperWA]

If/when tests succeed, this should be ready to go

[sphuber]

Thank you very much for your submission. We have thoroughly reviewed your screening but unfortunately, for us to be able to approve this with an MPA rating, we require one final adaptation to the cut. To make the presented film palatable to Oriental Audiences, the accompanying documentation will have to reflect the state of the code. We thank you for your cooperation

[CasperWA]

I've never really understood what is meant by 'redux' anyway

[sphuber]

Thanks a lot @CasperWA . As always, the director's cut extended edition is always the best