[Task]: Deprecate runner for Spark v2
What needs to happen?
It is time to deprecate the Spark 2 runner in Beam, see this discussion. Databricks is also dropping support for runtimes using Spark 2 by the end of June 2022.
With that the Spark 3 runner will become the default and only Spark runner.
Issue Priority
Priority: 2
Issue Component
Component: runner-spark