Fallback to the `Received` date when a proper `Date` header is missing

[pacien]

Is your feature request related to a problem? Please describe.
Emails which lack a proper Date header are displayed as if they were coming from January 1970 (unix epoch 0).
This is rather annoying because new emails which have this issue are displayed at the bottom of the inbox instead of the top.

Describe the solution you'd like
Some other email clients use the date present in the last (oldest) Received header as a fallback, which is sensible.

Describe alternatives you've considered
/

Additional context
/

[pazz]

Yes, I agree that this makes sense. The only such mails I have are alot test messages though :) PRs welcome. Quoting Notkea (2020-06-19 07:42:01)

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Is your feature request related to a problem? Please describe. Emails which lack a proper Date header are displayed as if they were coming from January 1970 (unix epoch 0). This is rather annoying because new emails which have this issue are displayed at the bottom of the inbox instead of the top. Describe the solution you'd like Some other email clients use the date present in the last (oldest) Received header as a fallback, which is sensible. Describe alternatives you've considered / Additional context / — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.*