Create 3 steps to Lightning guide to replace quick-start (Lightning-AI#3055)

* Update new-project.rst

* Update new-project.rst

* Create 3_steps.rst

* revert

* remove the callbacks vid

* fix blank line

* change ref

* spelling

* spelling

* Update docs/source/new-project.rst

Co-authored-by: Nathan Raw <nxr9266@g.rit.edu>

* spelling

* spelling

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Co-authored-by: William Falcon <waf2107@columbia.edu>
Co-authored-by: Nathan Raw <nxr9266@g.rit.edu>

Author: 3 people