[SWEET-5] Switch from scvpp to VOM

[vvalderrv]

scvpp had been initiated to get started quickly on the project but at the same time making two models of different family (openconfig and ietf) use the same functions.

scvpp is heavy to maintain because it is the job of sweetcomb developers to adapt to VAPI changes. It is also not very convenient to use C in some cases like when you receive multiple messages when performing a dump. This needs to implement linked lists based data structure which are always error prone.

The solution is to use VOM middleware which is officialy maintained by VPP and is part of VPP project. VOM offers an interesting abstraction layer which can be used to replay configurations in case VPP crashes. 

Thus, adopting VOM is a first step for a VPP+sweetcomb instance support High Availability.