Topic Creation API should not require the type-name and may take the topic name optionally too

[kydos]

The current API to define a topic requires a user to specify both the Topic type, the topic registration type and the topic name:

var topic = await vortex.CreateTopic (topicName,
topicType,
topicRegistrationType,
qos);

For consistency with other APIs and simplicity we should allow the "topicType" and more importantly the topic registration type to be just an option and deduce it automatically from the type parameter (ChatMessage below).

var topic = await vortex.CreateTopic (topicName, qos);

We could potentially also assume that TopicName == TopicTypeName when a topic is created as follows:

var topic = await vortex.CreateTopic ();

or like this:

var topic = await vortex.CreateTopic (qos);