Mask body in list or map format instead of string format

[stevehu]

We have a mask module to mask sensitive data from header, query parameter, path parameter and body. It works with JSON object with JSON Path with configuration. With the introduction of Body module that parses body of application/json to list or map, we need to update the mask module to work with list and map. Regarding to traverse the list or map, here is an example.
https://github.com/networknt/light-java/blob/master/sanitizer/src/main/java/com/networknt/sanitizer/SanitizerHandler.java

[lanphan]

I'll take this if @ddobrin busy, just because I'm reviewing this module

[ddobrin]

I have assigned this to you as well.

Please send a PR after you make changes. Thank you