Params Validation

// Considering that request with following payload has been sent:
{
  "member": { "first_name": "s", "msisdns": ["123", "4740769126",""] }
}

// Following response is returned: 
{
  "error": "Invalid parameters",
  "details": {
    "member": {
      "name": [
        { "error": "too_short", "options": { "min_length": 0 } },
        { "error": "invalid_format", "options": { "format": "/[A-Z][a-z]+/" } }
      ],
      "msisdns": {
        "0": [{ "error": "invalid_msisdn" }],
        "2": [{ "error": "blank" }]
      }
    }
  }
}

// It means that in given payload:
// * member.name is too short 
// * member.name has invalid format
// * member.msisdns[0] is not a valid MSISDN
// * member.msisdns[2] is blank