json log format updates
json log format updates

- change `message` to `msg`
- add `err` from `record.exception`

mozilla/fxa-auth-server,vladikoff/fxa-oauth-server,moander/fxa-oauth-server,mozilla/fxa-auth-server,mozilla/fxa-auth-server,rishibaldawa/fxa-oauth-server,moander/fxa-oauth-server,dannycoates/fxa-oauth-server,mozilla/fxa-auth-server,rishibaldawa/fxa-oauth-server,chilts/fxa-oauth-server,vladikoff/fxa-oauth-server,dannycoates/fxa-oauth-server,chilts/fxa-oauth-server