message: Add 'capabilities' field to Cognitive Services account properties.
diff: "description": "The internal identifier.",
  "readOnly": true
  },
  + "capabilities": {
  + "readOnly": true,
  + "type": "array",
  + "items": {
  + "type": "string"
  + },
  + "description": "Gets the capabilities of the cognitive services account. Each item indicates a specific feature is supported by this account. The value is read only and for reference only."
  + },
  "customSubDomainName": {
  "type": "string",
  "description": "Optional subdomain name used for token-based authentication."
  