fix(auth): support email otp length and expiry

[sweatybridge]

What kind of change does this PR introduce?

Bug fix #2802

What is the new behavior?

Adds email opt length and expiry config.

Additional context

Add any other context or screenshots.

[coveralls]

Pull Request Test Coverage Report for Build 11568762023

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 10 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.05%) to 59.765%

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Files with Coverage Reduction	New Missed Lines	%
internal/storage/rm/rm.go	2	89.53%
internal/debug/postgres.go	3	64.86%
internal/gen/keys/keys.go	5	12.9%

Totals
Change from base Build 11527891407:	-0.05%
Covered Lines:	6359
Relevant Lines:	10640

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💛 - Coveralls