Add Support for Interceptors

[yasirmhd]

Gson provides support for annotations at a class level which can be used for doing post processing or validation. Link with details are attached below :

https://github.com/google/gson/blob/master/extras/src/main/java/com/google/gson/interceptors/Intercept.java

The code for this can be easily generated where we can call these post the deserialisation has happened