conforming-agent: Add Schema Validation to Xml/JsonProvider

[drcgjung]

Description / As-Is

XML/JsonProvider convert any incoming message/request body into java structures. By knowing the execution environment, an attacker could try to design input structures in order to target the evaluation logic behind.

How it should be

XML/JsonProvider should validate incoming message/request bodies according to a set of allowed schemas. this restricts the opportunities to design arbitrary input structures.