Add support for Avro single-object encoding

[ByteMaDo]

We use KDI for one of our customers, who sends Kafka messages via the Avro single-object encoding specification.
This pull-request introduces support for this encoding type.

Implementation details:

• Our client does not (nor want to) utilize a schema registry. As a result, this implementation supports one or more provided schema files instead.
• The implementation requires apache-avro version 0.17.0 or later due to a bug in the fingerprint calculation in earlier versions.

We’re happy to address any feedback or suggestions to improve this pull-request further.

[rtyler]

@ByteMaDo at a high level this pull request looks good to me, can you rebase off of main and fix the conflict so it can merge cleanly?

[ByteMaDo]

I'll do that in the next few days :-)

[ByteMaDo]

Okay - I am not sure why synching my fork of delta-io/kafka-delta-ingest with main automatically closed this pull request.
However, I will either reopen or create a new one once i've finished the rebase. :-)

@rtyler I'm having the same build issues with the current main branch as described in #212. i.e. the described version issues with strum.
I'll go ahead with the pull request once the issue is fixed. In the mean time the single-object encoding lives on in this branch: https://github.com/ByteMaDo/kafka-delta-ingest/tree/soe-avro