Remove User Factory in favour of Specification pattern

[jorge07]

Fixes #96

[coveralls]

Pull Request Test Coverage Report for Build 303

• 16 of 18 (88.89%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.3%) to 95.318%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/Domain/Shared/Specification/AbstractSpecification.php	0	1	0.0%
src/Infrastructure/User/Specification/UniqueEmailSpecification.php	7	8	87.5%
<!--	Total:	16	18	88.89%	-->

Totals
Change from base Build 296:	-0.3%
Covered Lines:	509
Relevant Lines:	534

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💛 - Coveralls

[zerai]

Hi, checking uniqueness requirement in the handler is better (aggregate stay pure) in my opinion.

I have some doubt (theoretical) about implementation, I think 'UniqueEmailSpecification' is a normal domain service (change name in CheckUniqueEmail) if we use term "specification" should adhere at "specification "specification pattern" only 1 interface "SpecificationInterface" and UniqueEmailSpecification and other future specification class inherit from this interface. changing contract/interface broke the composition/chaining capabilities of this pattern.

Suggestion1: change the name of service, avoid confusion of the term 'specification'

Suggestion2: don't change the name but change the code and adhere to the pattern

[jorge07]

Hey @zerai thanks for your feedback.

Specification abstraction added 👍

[jorge07]

I keep uniqueness logic in the domain because is a requirement of the domain itself and IMO business rules when deeper, better.