Add class and member properties to the Attribute class

[ArnaudBuchholz]

Part of #222

As a developer, I want the attributes to document the class and member name it was used on to reuse this information in my coding

Acceptance criterias

• A method named getClassConstructor should return the Class where the attribute was declared
• A method named getMemberName should return the member name where the attribute was declared
• If the attribute was declared at the class level, the getMemberName method should return undefined
• If the attribute class is flagged as $singleton, the above methods should return null and undefined