Discussion - Remove DEX Runtime API from RPC.

[hbulgarini]

It seems there is an agreement that custom RPC calls should be avoided and query any runtime API by using state_call.
At the moment Trappist node is implementing a custom RPC call for the Dex pallet here.

The point to discuss and agree here is if the Dex custom RPC are really needed or if they can be replaced by using state_call.

Reference discussions:

paritytech/capi#228 (comment)
paritytech/substrate#12358

kudos to @evilrobot-01 for the head ups

[evilrobot-01]

I think the fact that the runtime API being upgradeable without needing a node redeployment is a nice property, despite the additional step of tunneling the runtime API call via state_call.

[valentinfernandez1]

I can take this, it really takes a few minutes