Json formatting option for logs or the ability to add local volumes to conatiners to overwrite logging config

Hello,

It would be great if there was an option to format the log data in json -- primary reason being logging/monitoring tools in the k8s ecosystem will automatically tokenize json formatted log data, eliminating the need to set up parsing rules for field-tokenization and new-line delimiters.

Reading through the project, it looks like the logging module's config can be overwritten with a file (exposed as an env variable), though the helm chart does not expose a volumes/volumeMounts config.

We'd be happy to put in this contribution ourselves (either approach) if the team is receptive to a PR, otherwise either option would be great -- though it might be more intuitive to expose an option to select the json formatter in a clear manner through the helm chart (ex: `jsonLogging: enabled`).

Thanks!