New course expert rule to test the date of the last attempt of a course element

A new expert rule is added to the course interpreter: getLastAttemptDate

The function can be used to get the date of the last time the user attempted the course element, e.g. launched the test. You could then prevent a user from doing the test twice within 24h hours with the following code:

( 
  (getAttempts("70323786958847") == 0)
  | getPassed("70323786958847")
  | ( (getLastAttemptDate("70323786958847") + 24h ) < now ) 
)