Make anonymizer more restrictive

These changes support a more restrictive anonymization for non-tta member access. Per a conversation with Reid, the approach taken was to use the existing shape of PPRs and set those attributes that could be sensitive to None or []. These attributes are:

vettingNotes = None proposal.authors = [] proposal.submittedTimeStamp = None proposal.authorCopy.modifiedTimeStamp = None proposal.authorCopy.allocationRequests = [] proposal.observatoryCopy.modifiedTimeStamp = None proposal.observatoryCopy.allocationRequests = []

In a future story, the less restrictive anonymization (the reviewer has certified conflicts) will be supported so only the following are anonymized:

vettingNotes = None proposal.authors = []