Update quickstart (#970)

* Add example project overview to quickstart

* Add example project description to quickstart

* Update dev model changes

* Define backfill

* Update docs/quick_start.md

Co-authored-by: Jo <46752250+GeorgeSittas@users.noreply.github.com>

* Update docs/quick_start.md

Co-authored-by: Jo <46752250+GeorgeSittas@users.noreply.github.com>

* Address PR comments

* Remove use of pipeline

* Wordsmith

* Remove pipeline and DAG

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Co-authored-by: Jo <46752250+GeorgeSittas@users.noreply.github.com>

Author: treysp