New subcommand for config introspection

[VihasMakwana]

Is your feature request related to a problem? Please describe.

It would make sense to have a command line option which logs the final configuration. It is particularly useful for users when a config is created from multiple providers and expanded recursively.

Describe the solution you'd like

This option can be provided as a subcommand (like validate subcommand). This new subcommand would be helpful for introspection the configuration.

Alternative options

Alternatively, we can create a new subcommand, --dry-run which both validate the config and print the final configuration. This is quite similar to helm's dry-run command.

Usage

1. Validate the config

otelcol dry-run

2. Validate the config and print the final configuration

otelcol dry-run --debug

[VihasMakwana]

I’m not entirely sure how this fits into the 1.0 roadmap, but I think it could be a valuable addition before the major release. I’d love to hear your thoughts on it!

[VihasMakwana]

Duplicate of #5223.