update documentation for configuring docker version about collector

[mgood]

#29 may also be of interest since it's requesting the ability to configure everything via environment variables, so you wouldn't need to inject a config file when using Docker.

[lfittl]

@oppianmatt Is the database you're looking to monitor in the cloud (e.g. RDS), or an on-premise database?

If its on RDS, all you need to set is PGA_ENABLE_LOGS. If its on-premise, 515202d might be the fix (allowing you to mount a volume that has the log files, and then monitor that), that will be in the next collector release.

I'm also adding a TODO item here to update the documentation, as this is currently confusing to read when using the Docker container.

[lfittl]

This is no longer necessary, as we now automatically enable Log Insights if you are connecting to a supported endpoint (e.g. RDS)