Implement Apache Avro encoder

[streamich]

We need to implement Apache Avro codec encoder in src/avro/ folder.

See Apache Avro specification: https://avro.apache.org/docs/1.12.0/specification/

• Add Apache Avro schema validator routine.
• Create AvroEncoder class which can write to Writer values, just values. encoder.writeNumber(num), etc.
• Create AvroSchemaEncoder class which can write to Writer data given schema. encoder.writeNumber(num, numSchema), etc.
• Add tests.

[github-actions]

🎉 This issue has been resolved in version 1.6.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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