Add esmvaltool config validate command?

[alistairsellar]

Is your feature request related to a problem? Please describe.
It might be useful to have an esmvaltool command to validate a config file. One can use the python API with esmvalcore.config.CFG to validate a config file, but as far as I can tell there isn't a command (short of trying to run a recipe).

This would be a potential solution to an issue with recipe_test_workflow, but there are other options for that if it's not desirable for some reason.

It would be added to the config command group and syntax would be

esmvaltool config validate <config_file.yml>

The idea would be to use the existing validation method that is done when running a recipe, just without running a recipe.

Would you be able to help out?
Yes, I would aim to write this if agreed to be useful.

[alistairsellar]

Does anyone in @ESMValGroup/technical-lead-development-team have a view on this proposal? Does such a command already exist? Does anyone have any objections to me adding it?

[valeriupredoi]

this would be very useful, and it harks back to my very distant in time trials to have a dry-run optionality ie do everything short of running a recipe: configuration validation, data availability checks, etc