Created AdminUser entity and provider

* Created entity, factory, repository
* Created provider for adminuser
* Also refactored the way this providers are built. Using abstract class
* Splitted configuration in several files on UserBundle package
* Created both abstract user registration event, and specific type of user event
Merge pull request #121 from elcodi/feature/user-admin-entity

User admin entity
Added object manager defs for Product entities
Merge pull request #123 from elcodi/feature/object-managers-config-product

Added object manager defs for Product entities
Fixed PrintMoneyExtension to accept nulls

* If null, print empty string
* if NullMoney, print empty string
Added getter and setter for dimensions
Merge pull request #125 from elcodi/hotfix/dimensions-getter-setter-product

Added getter and setter for dimensions
Added setters for Money fields

* Useful and needed for Form Component
* Money construct method set as protected
* Changed all old references to "new Money" and changed to make them use static factory
* Also fixed cs minor issue in ImageManager
Merge pull request #124 from elcodi/hotfix/money-extension-hotfix

Fixed PrintMoneyExtension to accept nulls
Merge pull request #126 from elcodi/feature/money-field-setters

Added setters for Money fields
Attribute and Value bundle

AttributeBundle defines the basic key/value model used to support
product configuration, i.e. descriptive attributes as well as "dimensions"
used to identify a particular variant of a product or product extras.
Fixes from php-cs-fixer
Fixed incorrect classname parameter and doctrine mapping
Added SKU for Product
Added Trait for price members in a Product
Initial product variant bundle structure and classes
Moved VariantInterface from Entity directory
Added ORM and Fixture configuration
Fixed circular interface between Product and ProductPrice
Reduced code duplication in tests AppKernel