[PROTOTYPE] Add unnamed types support

[Strech]

Resolves #95

This PR will add support for unnamed types. All codecs are going to support it. The only new limitation comes from Registry storage.

To "name" an unnamed type, we need its subject name and to get it we send a request to endpoint /schemas/ids/{id}/versions which exists only starting Confluent Schema Registry version 5.5.0.

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TODO

• [x] Complete all todo's in the code
• [x] Replace io.confluent namespace with io.acme
• [ ] Move confluent naming update into main
• [ ] Resolver should use new information about schema (name & version)
• [ ] Replace primitive schema with union and add tests on encoding/decoding
• [ ] Confirm that Registrar also works
• [ ] Update readme