populate basic key information (access mask, key type, expiration)
key expiration predicate (and temporary change of attribute type to Str, just until i get around to moving things to proper datetime objects)
key info attributes moved to rw/SetOnce
internal-use keyinfo() method in base class to prevent unnecessary calls to remote CCP API when creating subclass objects
need to declare the predicates if i expect to be able to use them
base class' BUILD checking for key information already being present before making remote API call