Add option to list configuration values optionally with origins

[GadgetSteve]

Current problem

When trying to debug pylint configuration issues it can be difficult to identify what the current configuration values are and where they came from, (CLI or actual config file path). Given the multiple possible setting origins, many platform dependent, identifying the origin of many configuration settings can be challenging.

Desired solution

When I am trying to resolve configuration issues I would like to be able to issue commands such as pylint --config-list and pylint --config-list-show-origin - then when it is suspected that a configuration issue if any is causing problems (e.g. not detecting an issue on one users machine that is reported on another or by CI/CT).

Additional context

This would be similar to the git config list and git config list --show-origin command like options which I have often had to call upon to resolve issues with git.

[Pierre-Sassoulas]

Thank you for opening the issue. I like the similarity of the proposed command to what git have.