{
  "properties": [
    {
      "name": "spring.cloud.gcp.logging.enabled",
      "type": "java.lang.Boolean",
      "description": "Auto-configure Google Cloud Stackdriver logging for Spring MVC.",
      "defaultValue": true
    },
    {
      "name": "spring.cloud.gcp.pubsub.enabled",
      "type": "java.lang.Boolean",
      "description": "Auto-configure Google Cloud Pub/Sub components.",
      "defaultValue": true
    },
    {
      "name": "spring.cloud.gcp.sql.enabled",
      "type": "java.lang.Boolean",
      "description": "Auto-configure Google Cloud SQL support components.",
      "defaultValue": true
    },
    {
      "name": "spring.cloud.gcp.trace.enabled",
      "type": "java.lang.Boolean",
      "description": "Auto-configure Google Cloud Stackdriver tracing components.",
      "defaultValue": true
    }
  ]
}


Add metadata for extra config properties
GH-973: Add metadata for extra config properties

Fixes https://github.com/spring-cloud/spring-cloud-gcp/issues/973

If configuration properties are not covered with the
`@ConfigurationProperties` class, there is no a JSON metadata generated
for them and content assistant in the IDE throws warning about not
existed properties

* Add `additional-spring-configuration-metadata.json` and describe all
the properties without `@ConfigurationProperties`
