integrated object cache into session and added message bus to object_cache and update tests

include/matador/object/object_proxy.hpp

@@ -53,6 +53,18 @@ public:
     }
   }
 
+  void resolver(std::weak_ptr<object_resolver<Type>> resolver) {
+    std::lock_guard lock(mutex_);
+    resolver_ = std::move(resolver);
+  }
+
+  [[nodiscard]] std::shared_ptr<Type> object() const {
+    if (!obj_) {
+      std::ignore = resolve();
+    }
+    return obj_;
+  }
+
   void invalidate() {
     std::lock_guard lock(mutex_);
     obj_.reset();