[CLI-3310] End-to-end example of flink UDF

[tmalikconfluent]

https://confluentinc.atlassian.net/browse/CLI-3310

Result after terraform apply:

Terraform plan result to ensure no TF drift:

References https://docs.confluent.io/cloud/current/flink/how-to-guides/create-udf.html

[confluent-cla-assistant[bot]]

:tada: All Contributor License Agreements have been signed. Ready to merge.
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