[Task]: Remove Flink 1.16 support and clean up

[kennknowles]

What needs to happen?

Flink 1.16 is very old and has been unsupported by Flink for a long time. We now support 1.17 and 1.18 and 1.19 so we can drop 1.16.

Issue Priority

Priority: 2 (default / most normal work should be filed as P2)

Issue Components

• [ ] Component: Python SDK
• [ ] Component: Java SDK
• [ ] Component: Go SDK
• [ ] Component: Typescript SDK
• [ ] Component: IO connector
• [ ] Component: Beam YAML
• [ ] Component: Beam examples
• [ ] Component: Beam playground
• [ ] Component: Beam katas
• [ ] Component: Website
• [ ] Component: Infrastructure
• [ ] Component: Spark Runner
• [X] Component: Flink Runner
• [ ] Component: Samza Runner
• [ ] Component: Twister2 Runner
• [ ] Component: Hazelcast Jet Runner
• [ ] Component: Google Cloud Dataflow Runner