AvroCoder - Support Logical Types

Context (from ASF Slack, BEAM channel):
```

Hey all!

So I've been working with the BEAM 2.4.0 Java SDK, and I am trying to see if Avro Logical
Types (https://avro.apache.org/docs/1.8.2/spec.html#Logical+Types) are supported within the AvroCoder.

From
what I'm seeing it doesn't seem to be the case, though maybe I'm missing something. Does it make sense
to allow for a user to supply a set of Conversion(s) to be used within the ReflectData in the AvroCoder?

```

Potentially relevant Apache Avro Bug: https://issues.apache.org/jira/browse/AVRO-1891

Imported from Jira [BEAM-4438](https://issues.apache.org/jira/browse/BEAM-4438). Original Jira may contain additional context.
Reported by: Nalseez.