[Task]: Tour of Beam Java Typos/Issues

### What needs to happen?

This also is true for the docs on this page: https://beam.apache.org/documentation/runners/spark/

This line, specifically: `Starting from Beam 2.20.0, pre-built Spark Job Service Docker images are available at [Docker Hub](https://hub.docker.com/r/apache/beam_spark_job_server).`

is out of date for the job service docker image. I believe now the correct link should be `https://hub.docker.com/r/apache/beam_spark3_job_server`

Additionally, it is a little ambiguous if and how the job service actually works. It implies, and other locations state, that it will submit the job to the spark server for you, but further down in the `Using spark-submit` section it says you still need to use that cli to submit jobs. Which is true?

This language is repeated in several places, including the docker image links, so clearing this up would be helpful. An example, even in pseudocode or diagram, would really help clear this up.

### 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
- [X] Component: Beam examples
- [ ] Component: Beam playground
- [ ] Component: Beam katas
- [X] Component: Website
- [ ] Component: Spark Runner
- [ ] Component: Flink Runner
- [ ] Component: Samza Runner
- [ ] Component: Twister2 Runner
- [ ] Component: Hazelcast Jet Runner
- [ ] Component: Google Cloud Dataflow Runner