Add env.php configuration and introduce Credit_Client Factory

[mwr]

This pull request will

• add env.php configuration for elgentos_largeconfigproducts
• use env.php configuration to create the Credis_Client
• fallback to the Settings stored in store config (core_config_data)
• refactor instantiation of Credis_Client to custom Factory

This way it is possible to have a custom configuration in you env.php, looking something like this:

  'cache' =>
  array (
    'frontend' =>
    array (
      'elgentos_largeconfigproducts' => [
        'backend' => 'Cm_Cache_Backend_Redis',
        'backend_options' => [
            'server' => '__REDIS_HOST__',
            'port' => '__REDIS_PORT__',
            'password' => '__REDIS_PASSWORD__',
            'persistent' => '',
            'database' => '__REDIS_DATABASE__',
        ]
      ],

The recently introduced way using the store-configuration in core_config_data will be used as a fallback mechanism to preserve backwards compatibility.

[simonmaass]

would be great!

[peterjaap]

LGTM!