Add plan name to deserialized topologies

[eazamaAU]

Is your feature request related to a problem? Please describe.
It would be nice to be able to implement Topic Validations against the topic's plan
The interface for topics includes a getPlan() method, however the deserializers do not populate this field.

Describe the solution you'd like
Modify the TopicCustomDeserializer to add the plan name to the topic.

Describe alternatives you've considered
External parsing of the topology file is cumbersome and requires re-inventing a validation mechanism