minor #885 Remove default private services config (Tobion)

This PR was squashed before being merged into the master branch (closes #885).

Discussion
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Remove default private services config

- the system cache uses apcu automatically when available, see https://github.com/symfony/symfony/blob/2bfcaeb31ff3b878734b0951851d25abf2b3321e/src/Symfony/Component/Cache/Adapter/AbstractAdapter.php#L109

- private services are the default now, see symfony/recipes@4c3d490

Commits
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a21b4d7 Remove default private services config

Author: javiereguiluz

config/packages/prod/framework.yaml

@@ -11,9 +11,6 @@ services:
     _defaults:
         autowire: true      # Automatically injects dependencies in your services.
         autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
-        public: false       # Allows optimizing the container by removing unused services; this also means
-                            # fetching services directly from the container via $container->get() won't work.
-                            # The best practice is to be explicit about your dependencies anyway.
         bind:               # defines the scalar arguments once and apply them to any service defined/created in this file
             $locales: '%app_locales%'
             $defaultLocale: '%locale%'