feat: improve / clean up logging

[jennifer-richards]

• Include more fields in JSON logs
• Extract gunicorn access log fields in JSON
• Put all gunicorn logs on stdout, leave django logs on stderr
• Replace syslog with Python logging (or remove the messages)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 41.66667% with 14 lines in your changes missing coverage. Please review.

Project coverage is 88.79%. Comparing base (187c2c5) to head (4571952). Report is 274 commits behind head on main.

Files	Patch %	Lines
ietf/utils/jsonlogger.py	35.00%	13 Missing :warning:
ietf/wsgi.py	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #7591 +/- ## ========================================== - Coverage 88.98% 88.79% -0.19% ========================================== Files 291 295 +4 Lines 40717 41270 +553 ========================================== + Hits 36233 36647 +414 - Misses 4484 4623 +139 ```

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