In T211141 we are allowing staff to automatically send users emails about suggestions they upvoted. We should give users the option of opting out of these emails while retaining their upvotes.
**Acceptance criteria**
* There should be a suggestion email user preference field
* Users can control this preference via the Emails section of their user page (https://wikipedialibrary.wmflabs.org/users/) - the text should say "Send notices when upvoted suggestions become available"
* The email sent to users by staff should the following additional sentence (bolded) near the end:
> You can now [apply for access to / access] [RESOURCE NAME] at [RESOURCE PAGE LINK].
>
> **These emails can be turned off in your user preferences: https://wikipedialibrary.wmflabs.org/users/ **
>
> If you have any issues or questions please contact us at wikipedialibrary@wikimedia.org