Adding `includeAdditionalProperties` = false(or true) in Validation option

[vivek656]

In Validation options , we can pass, format checking , unique key validation method etc. to customize our SchmeaValidator.

• It will be helpful if we can pass includeAdditionalProperty = false (true by default) , which will validate no addidtional property will be included in the object type.

This basically means, instiating the additionalPropertyValidator everytime , for every object type, if value is false. Many opensource schema , is used in various companies, many dont put additionalProperties = false on every object type field. Dev wants to work with these schema, but need a way to prevent adding additional non defined properties. these schemas can also be very large. This validationOption , help many to validate the constraint without altering the external schema.

[vivek656]

@worldturner can anyone reply to this . Adding additional validation at runtime, would be a gamechanger to this library