Issue #1981: MultiProvider RC and Extensions API implementation: redundant code in SmsService and SmmpMessageHandler

[abdulazizali77]

Code to process and handle extension hooks, ExtensionRequests and ExtensionResponse in SmsService and SmppMessageHandler are identical (executePreOutboundAction executePostOutboundAction handleExtensionResponse ). This could be centralized in the Extensions Controller implementation or the RC Bootstrapper implementation.
This requires design discussion and iterative implementation of the Extensions API and implementation design.
This is blocked by #2125 and #2126

[abdulazizali77]

@gvagenas This is already fixed in the 09b166d
so closing this