Bringing the hazelcast async executor up to speed with the latest changes in the DefaultAsyncExecutor (in fact, extending from it now)

EndEvent

when the first argument 'namespace' of BaseElement.getAttributeValue(String, String) is null, it should return the value of the first ExtensionAttribute whose 'namespace' field is also null

The message is originally written with hard code and should be modified to use i18nManager.

modified some tests to test full URL

ProcessEngineConfigurationImpl

ProcessEngineConfigurationImpl