Add user/session field to application logs

[Matt-Spence]

Issue description

Currently it is difficult to correlate logs for a given user/session. This can make debugging specific issues tricky. We should add a field to logs that enables us to filter them by user. This field should be user-specific but appropriate for inclusion in logs (e.g. an email address). This may be either a separate field within the log, or pre-pended onto the log message itself.

Acceptance criteria

• Logs include email address that enables them to be correlated by user.
• Enable these logs for sandboxes and stable (not local)

Additional context

No response

Links to other issues

• Relates to Add Router logging to make Cloud.gov logs better #3602

[PaulKuykendall]

For refinement, how big of a lift is this, and prioritize this.