Extend rubocop Rails.logger to prevent usage of AppLogger

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On gitlab-foss#54102 (closed) we added a rubocop for Rails.logger, we should extend this one to also prevent the usage of AppLogger.

From !17779 (comment 222741696)

We could easily replace it with a AppJsonLogger or something of the sort that inherits from JsonLogger: https://docs.gitlab.com/ee/development/logging.html