control-service: Format logs in JSON

[gabrielgeorgiev1]

Control Service logs must be able to be formatted in JSON using
an environment variable due to the importance of structured logging
capability. This change adds an encoder which formats logs in JSON
for an instance of the Control Service with the LOGGING_FORMAT
environment variable set to JSON.
This change allows us to retain the previous log config while
still allowing us the freedom to configure a logger to format logs
to JSON. Logging configuration should be much more in depth,
however it would require changes outside of the scope of the
current story.

Testing done: ran CS with the encoder set for local logs and the
LOGGING_FORMAT env variable set to JSON and observed the logs,
also with other values and saw that the logs were formatted in
the default format.

Signed-off-by: gageorgiev gageorgiev@vmware.com

[antoniivanov]

In the commit message, the problem statement can be generalized. We are not adding some specific support for Kibana. What we are doing would make it better for Kibana users.
But not just only that we want logs to be visible in Kibana. We want to enable structured logging in Control Service (https://stackify.com/what-is-structured-logging-and-why-developers-need-it/) which enables a lot of benefits for developers (explained in the article I linked - I picked the first I googled - there a lots.). It makes it easier to filter and browse in modern logging tools (like Kibana but also other like log intelligence or Loggly and so on).

Please fix it since some reading it may think this is a very specific feature and it is not.

[antoniivanov]

I almost forgot :

From https://github.com/vmware/versatile-data-kit/blob/main/CONTRIBUTING.md#how-to-submit-and-merge

projects/*/CHANGELOG.md Next version section should be updated accordingly.

/offtopic:
Maybe We need to think how to automate changelog updates. I forget often to do it.
Maybe can automatically create it from the commit message. But then we'd need more structured commit messages.
/end offtopic.