Update enum values for BigQuery dataset location

[moszutij]

I've aligned the enum values for BigQuery dataset location with the values defined in https://cloud.google.com/bigquery/docs/locations. I've added a bunch of regional locations but also removed Asia as this is no longer a valid value. This can be seen from the error response below:

ERROR: (gcloud.deployment-manager.deployments.create) Error in Operation [operation-1559562795381-58a6a026c74b5-2b665e25-36a38bfb]: errors:
- code: RESOURCE_ERROR
  location: /deployments/enterprise-006/resources/ENTERPRISE
  message: '{"ResourceType":"bigquery.v2.dataset","ResourceErrorCode":"400","ResourceErrorMessage":{"code":400,"errors":[{"domain":"global","message":"Invalid
    value for: Asia is not a valid value","reason":"invalid"}],"message":"Invalid
    value for: Asia is not a valid value","statusMessage":"Bad Request","requestPath":"https://www.googleapis.com/bigquery/v2/projects/tactical-hydra-999999/datasets","httpMethod":"POST"}}'