plumbing to make auth0-less users work in the website (#2398)

* [www] plumbing to make auth0-less users work in the website

* [www] fix and separate verification-email feature

* [snack] nickname->username

* [www] fix plubming, expo admin

* [xde] fix toolbar nickname -> username

* [snack] nickname -> username

* [www] deprecate nickname, support it going backwards

* [www] nickname -> username

* [www] fix flow errors

fbshipit-source-id: 7473327

Bump version

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Bump version

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Bump XDL version to 48.1.4 and bump XDE patch version

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Bump versions

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Update repo from exponent to expo

fbshipit-source-id: 4c0d16f

Bump version to 2.22.1

fbshipit-source-id: 9d79d68

Bump version to 2.22.0

fbshipit-source-id: 307ba71

bump versions

fbshipit-source-id: 5676185

bump versions

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