Update ConfigureRegion for new global OAS server format

[vicentepinto98]

With the migration to the stackit-api repo, the generated OAS for global APIs will have a different server url that follows this pattern:

"servers": [
    {
      "url": "https://identifier.api.stackit.cloud",
      "variables": {
        "region": {
          "default": "global"
        }
      }
    }
  ]

This PR updates the ConfigureRegion method to take into account this change

[joaopalet]

So for regional APIs the URL will still contain the template, right?

[vicentepinto98]

So for regional APIs the URL will still contain the template, right?

Yes, that way we can configure multiple regions, as long as they are defined in the OAS