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

There is a --quiet global option for composer: https://getcomposer.org/doc/03-cli.md#global-options

But it can't be set from an environment variable.

Describe the solution you'd like

Proposal: add a COMPOSER_QUIET option that enable the quiet mode.

Describe alternatives you've considered

Alternatively, we could call Composer from CLI to add the option, but I think that the environment variable can be helpful in many contexts.

Additional context

The context is a CI environment where composer is ran automatically and we can't add CLI options, but we can set environment variables, like COMPOSER_IGNORE_PLATFORM_REQ: ext-mongodb.