private static DocprocChain getDefaultChain(ContainerDocproc docproc) {
        return docproc == null
                ? null
                : docproc.getChains().allChains().getComponent("default");
    }
Create the {@code default} and {@code default-get} routes for the Document protocol. The {@code default}
route will be either a route to storage or a route to search. Since recovery from storage is supported,
storage takes precedence over search when deciding on the final target of the default route. If there
is an unambiguous docproc cluster in the application, the {@code default} route will pass through it.
The {@code default-get} route skips the docproc but is otherwise identical to the {@code default} route.

@param content the content model from {@link com.yahoo.vespa.model.VespaModel}
@param containerClusters a collection of {@link com.yahoo.vespa.model.container.ContainerCluster}s
@param table the routing table to add to
config-model/src/main/java/com/yahoo/vespa/model/routing/DocumentProtocol.java