src: fixed some clang tidy warnings

* implemented CxxDeclName constructors that just move the members
* removed empty destructors because they disable default move constructors
* removed some unnecessary code
* replaced ".size() == 0" with ".empty()" because it's more explicit

src/lib_java/data/parser/java/JavaEnvironmentFactory.cpp

@@ -34,7 +34,7 @@ void JavaEnvironmentFactory::createInstance(std::string classPath, std::string&
 		errorString
 	);
 
-	if (!createInstanceFunction && errorString.size() > 0)
+	if (!createInstanceFunction && !errorString.empty())
 	{
 		return;
 	}