[2.3] [Serializer] Enabled camelCase format to be used on denormalize method

 Enabled camelCase formater , that way when hydrating from arrays, attributes as attribute_name could be implemented as attributteName parameter, with getAttributeName and setAttributeName, giving different formating option from setAttribute_name  getAttribute_name.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | no
| License       | MIT
| Doc PR        | no