Add a cron for regular / maintenance tasks

[dpi209]

We need crons for periodically executed tasks. Examples:

• sending information to scistarter
• cleaning up old sessions from the session db

[KeeperOfMaps]

Are all the tasks you're thinking of in the database or do some interact with other places? (I'm guess that sending info to scistarter is probably in the latter category.)

[KeeperOfMaps]

So I don't forget for later: look at maintaining sessions table via a stored procedure or a trigger.