Block storage migration azure (#7156)

* Import from external editor

* Copy edits

* Copy edits

* Copy edits

* Copy edits

* Copy edits

* Copy edits

* Copy edits

* Copy edits, add diagram

* Update diagram

* copy edits

* typo fix

* Remove failover guide from PR

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Co-authored-by: John Dutton <[email protected]>

Author: nmelehan