make certificate lifetime accessible through Tor's ControlPort

I am referring to the following. Sometimes user Tor logs contain something like this.

Sep 03 10:32:59.000 [warn] Certificate already expired. Either their clock is set wrong, or your clock is wrong.
Sep 03 10:32:59.000 [warn] (certificate lifetime runs from Aug 16 00:00:00 2014 GMT through Jul 29 23:59:59 2015 GMT. Your time is Sep 03 10:32:59 2015 UTC.)

This information is interesting in context for anonymity distributions and secure network time synchronization, usability and whatnot. Used by Tails' tordate or Whonix's anondate.

However, these tools rely on parsing Tor's log, which is fragile.

It would be nice, if something like

certificate/valid-after
and certificate/valid-until

where accessible through Tor's ControlPort.

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