File-based logging should support rotation

[azasypkin]

Depends on #12852.

We should support at least size-based and time-based triggering policies.

[azasypkin]

Note to myself: use new utils.promisify for file stream methods.

[epixa]

I'm going to close this as a duplicate of #12259. I know this issue was targeting new platform specifically, but log rotation of only new platform logs doesn't make any sense. It's possible the way we want to solve this problem is to move all logging over to the new platform logger first, which could be a reasonable approach, but that would still be Kibana-wide log rotation.