Support location.positions in code climate MR-widget

What does this MR do?

Support both forms of code climate issue-locations https://github.com/codeclimate/spec/blob/master/SPEC.md#locations

{
  "path": "path/to/file.sh",
  "positions": {
    "begin": {
      "line": 3,
      "column": 10
    },
    "end": {
      "line": 4,
      "column": 12
    }
  }
}

What are the relevant issue numbers?

Resolves #6813 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• EE specific content should be in the top level /ee folder