[Cookbook][External Parameters] Enhance description of environment variables
feature #4269 [Cookbook][External Parameters] Enhance content (bicpi)

This PR was merged into the 2.3 branch.

Discussion
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[Cookbook][External Parameters] Enhance content

Enhance description of environment variables used as container parameters

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | no
| Applies to    | all
| Fixed tickets | -

Commits
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93684e2 [Cookbook][External Parameters] Enhance description of environment variables