Container host metrics and bug fixes

Changed

• Log debug messages and warnings from the config initialization. Previously, any debug messages or warnings that should have been logged upon config initialization where not logged. Now, all config log messages are logged, including debug messages even if the log level is configured as info. This may be improved in the future.
• Shut down the collector in case of an internal error. We've seen problems where internal channels close and it causes the collector to stop reporting data. In this case, log what happens and shut down.

Fixed

• Disable the host metrics only on the collector container, by default. When the collector is installed on a container alongside the app, it will collect container host metrics.

This release can be installed through our collector packages and Docker image.