Adding a reminder job configurable per poll

[dartcafe]

Added an autoreminder, which can be activated in date polls and in polls, where an expiration date is set.

The automatic reminder is sent to all shares via email, triggerd by cron

For polls with expiration

• 48 hours before the expiration date, if the poll is created more than 5 days before the expiration.
• 36 hours before the expiration date, if the poll is created more than 2 and less than 5 days before the expiration.

For date polls without expiration

• 48 hours before the first date option, if the poll is created more than 5 days before the expiration.
• 36 hours before the first date option, if the poll is created more than 2 and less than 5 days before the expiration.

No reminder is sent

• for text polls without expiration.
• for polls created less than 2 days before the expiration
• if a share already got a reminder (no matter, if the expiration date got changed)
• if the poll is already closed

relates #1305
fixes #656

[joesch2]

In my opinion, it would also be useful to only remind those participants who have not yet voted.

[dartcafe]

How can we determine, who has NOT voted if he is not invited?

[joesch2]

You're right ;-) I put it differently:
To send an email, I need an email address. If someone does not vote anonymously, the system knows the user account and their email address. No notification should be sent to them if the vote has already taken place. If the user voted anonymously, it is not possible to make this distinction.

[dartcafe]

What is missing, is sending reminders to people which did vote, but are not invited. This is on the list and will come later.

But for the future: Please add a new issue rather than commenting in closed issues, because these comments may be overseen.