Debugging permission issues normally requires to know in which groups
the calling user is a member. Make this information available in traces.
Example log entry:
[2018-08-30 15:26:49,989] [HTTP-87] TRACE com.google.gerrit.server.IdentifiedUser : Known groups of admin: [157e8dff6c25b2b1955df92fecdb961a52fa6160, global%3ARegistered-Users, 5ef73722ea07c54f62e4b02ea414d262c0a2e046, ca1fd42646e71d8081add52fbb0171a8504c97cd, global%3AAnonymous-Users]
Change-Id: Ibca0cb15d4e63540c7b6e4663ec1decb7d393d25
Signed-off-by: Edwin Kempin <ekempin@google.com>