Default provider should not be equal to local host

[Yashk767]

Description

Right now in constants.go on oracle node

var DefaultProvider = "http://127.0.0.1:8545"

default provider is set to local host which only supports hardhat network which is incorrect as node uses default provider value when provider is not set in config file, which can result in error for contract calls due to incorrect RPC for given network .

Solution

Remove default provider, and node should return error if provider is not set in config file.