Add healthcheck to operator container

[Hyodar]

We have an external healthcheck in the docker compose environment, but it'd be nice to have it directly in the image.

[Hyodar]

Once we do this, then the test from #244 should be changed to check the health of the operator services directly

[mikhailUshakoff]

I'm unsure whether we should include a health check inside the container. I don't see any benefits from it. Moving the logic from the health container to the operator container wouldn't change anything. Perhaps we should consider a more sophisticated health check algorithm.

[Hyodar]

Hey, this is mostly a best practices thing. The container itself should have a general way for you to check if it`s healthy or not - you can always override it, but overall a separate service is not ideal. We did have a separate service before since our container had only the bare minimum infra.