schema timestamps

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

We should provide createTimestamp and modifyTimestamp
in subschema entries. 

I'm thinking we should set these based upon
creation/modification times of configuration
files.  The task would be to set createtime to the
oldest creation time and modifytime to the newest modify
time of the configuration times.  This can easily be
done fstat(2)'ing each file as they are being read.
Then generate createTimestamp/modifyTimestamp based on
these variables.

Volunteers?