Change JSON logs to use bunyan format

[dekobon]

Proposed changes

This change will change the format of the structured logging emitted by the Python and Java applications to the bunyan format. This will allow us to use third-party tools to view the logs in a human friendly manner.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• [X] I have written my commit messages in the Conventional Commits format.
• [X] I have read the CONTRIBUTING doc
• [X] I have added tests (when possible) that prove my fix is effective or that my feature works
• [X] I have checked that all unit tests pass after adding my changes
• [X] I have updated necessary documentation
• [X] I have rebased my branch onto master