Add optional schema registration to `Avromatic::Model::Messaging` Module

[dstrates]

Feature Request

Update the Avromatic::Model::MessagingSerialization module to make schema registration with the schema registry optional.

Current Behaviour

Currently, the MessagingSerialization module automatically registers the Avro schemas (both key and value schemas) with the schema registry when the register_schemas! method is called. This behaviour is always on, with no option to disable it.

Proposed Change

Introduce a class-level configuration option to control whether schemas should be registered automatically. This will allow developers to opt-in or opt-out of schema registration based on their specific use cases. This could potentially take the form of a class-level variable and methods to toggle the registration behaviour.