Auto-close projects and notify users

[jaragunde]

When a project goes beyond its end date, it should either be closed or extended (end date changes). For that reason, we're proposing to implement a periodic task to check the status of project end date. It should work like this:

• It runs daily.
• Checks projects ending in one week or another configurable amount of time and send an email to project members and project managers (configurable). The text of the message should be configurable, too.
• Checks projects which end date is older than a configurable amount of time, and close them.

[jaragunde]

Likewise, this script could also open closed projects where the start date is in the future, e.g. projects which haven't started yet.

[dmtrek14]

Possibly related to #152