[1.8.x] Fixed #25178 -- Added DEFAULT_FROM_EMAIL to deployment checklist.

If your site sends emails, these values need to be set correctly.

By default, Django will send email from root@localhost. However, some mail

providers reject all email from this address. To use a different sender

address, modify the :setting:`SERVER_EMAIL` setting.

By default, Django sends email from webmaster@localhost and root@localhost.

However, some mail providers reject email from these addresses. To use

different sender addresses, modify the :setting:`DEFAULT_FROM_EMAIL` and

:setting:`SERVER_EMAIL` settings.

:setting:`STATIC_ROOT` and :setting:`STATIC_URL`

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