Eliminate dependency on doctrine/common

What is used through doctrine/common dependency:

Doctrine\Common\Util\Debug - likely to be dropped, only used in one console command and one test
Doctrine\Common\Event* to be extracted to doctrine/event-manager (for now)
Doctrine\Common\Persistence -> needs doctrine/persistence
Doctrine\Common\Util\Inflector -> should be switched to doctrine/inflector
Doctrine\Common\Lexer -> should be switched to doctrine/lexer (later removed)
Doctrine\Common\{PropertyChangedListener,NotifyPropertyChanged} -> likely to be merged into ORM

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