Provide an abstract logger.channel declaration

Problem/Motivation

logger.channel.default:
    class: Drupal\Core\Logger\LoggerChannel
    factory_method: get
    factory_service: logger.factory
    arguments: ['system']
  logger.channel.php:
    class: Drupal\Core\Logger\LoggerChannel
    factory_method: get
    factory_service: logger.factory
    arguments: ['php']
  logger.channel.image:
    class: Drupal\Core\Logger\LoggerChannel
    factory_method: get
    factory_service: logger.factory
    arguments: ['image']
  logger.channel.cron:
    class: Drupal\Core\Logger\LoggerChannel
    factory_method: get
    factory_service: logger.factory
    arguments: ['cron']
  logger.channel.form:
    class: Drupal\Core\Logger\LoggerChannel
    factory_method: get
    factory_service: logger.factory
    arguments: ['form']

Proposed resolution

  logger.channel.default:
    parent: logger.channel_base
    arguments: ['system']
  logger.channel.php:
    parent: logger.channel_base
    arguments: ['php']
  logger.channel.image:
    parent: logger.channel_base
    arguments: ['image']
  logger.channel.cron:
    parent: logger.channel_base
    arguments: ['cron']
  logger.channel.form:
    parent: logger.channel_base
    arguments: ['form']

Remaining tasks

review/commit

User interface changes

None

API changes

None