Stop using Kafka's Serde and add a real, composable Serializer/Deserializer

[iravid]

We should hardcode the consumer to K = Array[Byte] and V = Array[Byte], and provide data types that describe serialization/deserialization to and from byte arrays.

These data types should also be derivable from Kafka's existing Serde to ease migration.

As part of moving to these codecs, we should consider what interface to provide on the consumer for handling de/serialization failures. It's easy to just send a stream of eithers, but that is not very performant or ergonomic.

[svroonland]

I can see three desirable ways of handling deserialization failures:

1. Fail the stream
2. Skip the message
3. Allow the client to handle it explicitly

1 should be easy (already the case?)
3 can be done by sending Eithers like you mentioned.
Maybe 2 can be implemented with some sort of onDeserializationError: DeserializationFailure => UIO[Unit] parameter on the plainStream and partitionedStream methods?

[iravid]

Resolved by #37. I'll open a follow-up for the failure handler