Include subjectName in membership changelog entries

[jfwillia]

Currently in membership type changelogs, only the subjectId is logged. While useful to Grouper users, subjectName is more often referenced and meaningful to Google Admins and can save some steps when troubleshooting issues.

Currently:

Google Apps Consumer 'google' - Change log entry 'ChangeLogEntry[timestamp=2018-06-05 12:57:04.473,sequence=16034723,category=membership,actionName=addMembership,contextId=56a9fbb8cb1d4bc696b4811419da4d1b,id=e0cc914fc95d4b9a8c9ef9a6ad3158c6,fieldName=members,subjectId=777777,sourceId=uncg-person,membershipType=flattened,groupId=51f5863f44d24a4badc7156e43f4ab0d,groupName=uncg:apps:AAA_test:bushyTestGroup,memberId=afb3efc0fa2447d9b9440d386b6c4247,fieldId=daf3e08d291e464aa5feda14b7ff4e72,subjectIdentifier0=]'

Proposed:

Google Apps Consumer 'google' - Change log entry 'ChangeLogEntry[timestamp=2018-06-05 12:57:04.473,sequence=16034723,category=membership,actionName=addMembership,contextId=56a9fbb8cb1d4bc696b4811419da4d1b,id=e0cc914fc95d4b9a8c9ef9a6ad3158c6,fieldName=members,subjectId=396705,subjectName="John T Spartan",sourceId=uncg-person,membershipType=flattened,groupId=51f5863f44d24a4badc7156e43f4ab0d,groupName=uncg:apps:AAA_test:bushyTestGroup,memberId=afb3efc0fa2447d9b9440d386b6c4247,fieldId=daf3e08d291e464aa5feda14b7ff4e72,subjectIdentifier0=]'