1.42.2: Feature/pro 901 implement batching for rates in SDK (#201)

* Added batching for fetching exchange rates

* Manged to return uniqueresult and updated the package version

* Fixed linting and rejected calls

* Fixed deep scan changes

* Handled error message for success result

* Fixed deep scan issues

* Have added test cases for fetching rates and removed consoles

* Updated node version to 12 in yml file

* Updated version for linter only

* Updated the example files