Create a link. You must supply either `pattern` or `external_url` in the request, but not both (`pattern` is for application objects while `external_url` is for standard links). If `pattern` is provided, the API call updates the application objects matching the exact pattern. Keep in mind this endpoint only creates or updates an existing link from an application object. It does not create new application objects. If the link is resolved to an installed links integration, any name retrieved from the integration will override the provided name in the request. Required scope: `links:write`