Simplify and improve the OSS Quickstart guide

[ian-at-airbyte]

Page URL

https://docs.airbyte.com/using-airbyte/getting-started/oss-quickstart

Description

For many, the open source Quickstart guide is one of the first interactions they'll have with Airbyte. However, the current version of this guide is not "quick" in nature, and it contains a great deal of superfluous or more advanced information. This has helped make the topic one of our most downvoted documentation topics. For a fuller analysis of deployment docs issues, see This Google Doc.

Fixing this topic should be our first priority on the road to more user-friendly, user-oriented, goal-based deployment documentation. This task will rewrite the Quickstart as an extremely focused, straightforward explanation of how to set up a local instance of Airbyte. All other information will be preserved for posterity or moved to the Deployment section for future revision.