Add the DoctrineOrm component

[qzminski]

This pull request adds the Doctrine ORM features such as:

• [x] Allow to bind the entity to a form.
• [x] Allow to automatically update Haste-ManyToMany relations.
• [x] Enable Contao versioning for an entity.
• [x] Enable Contao "undo" feature for an entity.
• [x] Documentation: https://github.com/codefog/contao-haste/blob/feature/doctrine-orm/docs/DoctrineOrm.md
• [x] Form documentation: https://github.com/codefog/contao-haste/blob/feature/doctrine-orm/docs/Form.md#bind-entity-to-the-form