Support setting service parameters via environment variables

Just override the parameter from your own ServiceProvider.

Instead of using symfony magic and replace the way the container is being built, use the drupal/symfony way to alter services/parameters in the container:
https://www.drupal.org/docs/drupal-apis/services-and-dependency-injectio... →

In essence what we did is to create file: my_module/src/MyModuleServiceProvider.php (the name matters) looks like this:

namespace Drupal\my_module;

use Drupal\Core\DependencyInjection\ContainerBuilder;
use Drupal\Core\DependencyInjection\ServiceProviderBase;

class MyModuleServiceProvider extends ServiceProviderBase {
  /**
   * {@inheritdoc}
   */
  public function alter(ContainerBuilder $container) {
    $cors_config = $container->getParameter('cors.config');
    $cors_config['allowedOrigins'] = ['https://' . $_ENV['CONSUMER_HOST']];
    $container->setParameter('cors.config', $cors_config);
  }
}

Make sure clear cache (so container will be compiled fresh) - drush cr / drush cc container

@bircher
I added some basic test coverage for resolving the env variable at compile time.

I'm also playing around with the idea to support using environment variables during runtime, see the --runtime branch.
This is clearly a bit more involved, and I think belongs really into its own issue in the first place.

@jkdev by doing it that way the values from environment variables are cached in the container, which means you need to rebuild caches anytime an environment variable is changed. I don't think we want that.

@duadua looks like you haven't pushed anything yet to the issue-3249970--runtime and 3249970-support-setting-service branches. I'm not sure why, but it contains some commits from other issues. Only issue-3249970 contains relevant commits.