add support to map sub items in an object to valuePath

[ahemed-haneen]

in cases where tables are not a single layered but have objects in some keys, but we want to display it in a single layer it would be better to support mappings to inner keys

for ex:

user = {
name: "something",
age: 10,
address: {
city: "somewhere",
country:"somewhere",
}}

if we want to display all this info in a table as a single layer, we right now cannot provide value paths like valuePath: "address.city" adding support to this would be very useful