Retrieve order partial filled values from Relay

[JoaoCampos89]

Right now, the relay does not retrieve the partially filled value of each order on the orderbook. This is necessary to the UX to not display the full amount on the orderbook or to show to the user that they have less balance locked on the order, as the order was already filled.

Three approaches can be done here to help solve this:

• Add the partial value on the meta object of signed orders using orderWatcher
• Create an endpoint that retrieves the partially filled order values, this helps to create an endpoint for market history
• Create a Post endpoint where we post the order that was filled from frontend, and then it calls orderWatcher for that specific order hash.