feat: add authorized email address support

[hf]

Adds support for authorized email addresses, useful when needing to restrict email sending to a handful of email addresses. In the Supabase platform use case, this can be used to allow sending of emails on new projects only to the project's owners or developers, reducing email abuse.

To enable it, specify GOTRUE_EXTERNAL_EMAIL_AUTHORIZED_ADDRESSES as a comma-delimited string of email addresses. The addresses should be lowercased and without labels.

Labels are supported so emails will be sent to someone+test1@gmail.com and someone+test2@gmail.com if and only if the someone@gmail.com address is added in the authorized list.

Not a substitute for blocklists!

[coveralls]

Pull Request Test Coverage Report for Build 10665862666

Details

• 36 of 36 (100.0%) changed or added relevant lines in 10 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.03%) to 57.894%

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Totals
Change from base Build 10665007028:	0.03%
Covered Lines:	9138
Relevant Lines:	15784

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💛 - Coveralls