CDR metadata

[dmitry-sinina]

When Cdr/Cdr policy rule has allow_metadata: true

Cdr/Cdr:
    allow_metadata: true

we have to display CDR metadata attribute value on CDR show page /cdr/<id> on dedicated tab as formatted json, example:

{
  "test": "value",
  "data": {
    "key": "value",
    "array": [
      "1",
      "2",
      "3"
    ]
  }
}