[Task]: YAML - E2E example pipelines for common use cases

### What needs to happen?

Adding E2E example pipelines based on common. use cases.

- [x] Phase 1 - Reorganize example location and add blueprints section - https://github.com/apache/beam/blob/master/sdks/python/apache_beam/yaml/examples/README.md
https://github.com/apache/beam/pull/35038
https://github.com/apache/beam/pull/35040
https://github.com/apache/beam/pull/35054
- [x] Phase 2 - High probable usage with yaml components ready
https://github.com/apache/beam/pull/35279
- [x] Phase 3 - Moderate probable usage with yaml components ready
https://github.com/apache/beam/pull/35423
- [x] Phase 4 - Low probable usage with yaml components ready
https://github.com/apache/beam/pull/35423
~~- [ ] Phase 5 - Update yaml generated docs after Phase 4 is complete~~ - Will be covered by release process.
- [ ] Phase 6 - Moderate probable usage, but waiting on yaml components being ready
gcs_avro_to_cloud_bigtable
mongodb_to_bigquery - Missing MongoDb
bigquery_to_bigtable
cloud_pubsub_to_splunk - Missing Splunk
~~- [ ] Phase 7 - Update yaml generated docs after Phase 6 is complete~~ - Will be covered by release process.

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