Add an option to _not_ register the created conda environments in ~/.conda/environments.txt

[jaimergp]

Checklist

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• I searched open requests and couldn't find a duplicate

What is the idea?

Some applications use conda internally and deploy installers with constructor (e.g. napari, Spyder, etc). While these installations will have one (or more) conda environments, their presence in ~/.conda/environments.txt might undesired for some maintainers.

I am adding conda/conda#12924 to have this feature in conda first. Then we can add an option in construct.yaml.

Why is this needed?

Better control over which environments are registered (and exposed) in the environments.txt file.

What should happen?

When the new option (e.g. register_envs) is set to False the resulting environments (the installation itself and the extra_envs, if any) should not appear in ~/.conda/environments.txt.

Additional Context

Initially reported at napari/packaging#83