Generator: Avro LogicalConverter

[lostiniceland]

Implementing a Avro-Converter
https://avro.apache.org/docs/++version++/api/java/org/apache/avro/Conversion.html (also includes how to register via seriviceloader)
should allow a definition like

avdl

@namespace("com.example")
protocol MyProtocol {

  record Order {
    @logicalType("quantity")
    int amount;
    string orderId;
  }
}

avsc

{
  "type": "record",
  "name": "Order",
  "namespace": "com.example",
  "fields": [
    { "name": "amount", "type": { "type": "int", "logicalType": "quantity" } },
    { "name": "orderId", "type": { "type": "string"} },
  ]
}