Feature/qeng 969 add modify tk config dsl method

HOCON is a superset of JSON, which means if I understand correctly, that a parser which correctly parses HOCON/typesafe will also correctly parse JSON. Which might lead you to question why we are even bothering with the JSON module...I just added it to be safe, in case the ruby-hocon library which is still very immature, doesn't actually parse JSON correctly for whatever reason.