feat: Migration guide (#289)

* Initial draft

* Small updates

* Spaces not tabs?

* more table formatting

* Update intro sentence

* Apply suggestions from code review

Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: David <[email protected]>

* Address feedback round 1

* Apply suggestions from code review

Co-authored-by: joe petrowski <[email protected]>

Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: David <[email protected]>