Get the array of site schema types.
array An array of typed data ids (entity_type and bundle) keyed by corresponding site schema URI.
public function getTypes() {
$cid = 'rdf:site_schema:types';
$cache = $this->cache
->get($cid);
if (!$cache) {
$this
->writeCache();
$cache = $this->cache
->get($cid);
}
return $cache->data;
}