`lobster-codebeamer` shall support upstream references

[phiwuu]

There is no way to verify the traces from codebeamer requirements to other codebeamer requirements, because the output file of lobster-codebeamer does not contain a refs section.

Below is an excerpt of an example codebamer.lobster file that now contains a ref section:

  "data": [
    {
      "tag": "req 649259",
      "location": {
        ...
      },
      "name": "example requirement",
      "messages": [],
      "just_up": [],
      "just_down": [],
      "just_global": [],
      "framework": "codebeamer",
      "kind": "Technical Requirement",
      "text": null,
      "status": "Valid"
      "refs": [
        "req 12345",
        "req 67890"
      ],
    },

This requires some kind of configuration. In the above example the codebeamer item 649259 can have an attribute called derived from, and contains links to items 12345 and 67890.

Furthermore, there is no way to specify the following values:

• just_up
• just_down
• just_global

I have created https://github.com/bmw-software-engineering/lobster/issues/50 for these configuration parameters. The current ticket shall only focus on the refs section.

[phiwuu]

Note: We should implement https://github.com/bmw-software-engineering/lobster/issues/49 first.