[yaml] Add Beam YAML Day Zero guide

[Polber]

What would you like to happen?

This bug is part of the Beam YAML milestone. More information about Beam YAML can be found here: https://github.com/apache/beam/tree/master/sdks/python/apache_beam/yaml#beam-yaml-api

A Beam YAML contribution guide can be found here: https://s.apache.org/beam-yaml-contribute

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A doc/notebook that describes first steps to creating a Beam YAML pipeline will help new users get started with using this new way to interface with Apache Beam.

Issue Priority

Priority: 2 (default / most feature requests 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: Spark Runner
• [ ] Component: Flink Runner
• [ ] Component: Samza Runner
• [ ] Component: Twister2 Runner
• [ ] Component: Hazelcast Jet Runner
• [ ] Component: Google Cloud Dataflow Runner

[Polber]

.remove-labels io,java,python