Updated and refactored Kafka GSR AVRO example

[nicusX]

Purpose of the change

Update AVRO GSR Kafka example

Verifying this change

Run locally and on MSF

Significant changes

• Completely new example
• Updated an existing example to newer Flink version or dependencies versions
• Improved an existing example
• Modified the runtime configuration of an existing example (i.e. added/removed/modified any runtime properties)
• Modified the expected input or output of an existing example (e.g. modified the source or sink, modified the record schema)