Merge branch 'policy/implement-contextService-interface' into 'develop'

src/policy/src/main/java/eu/teraflow/policy/Serializer.java

.../main/java/eu/teraflow/policy/context/ContextGateway.java

...n/java/eu/teraflow/policy/context/ContextGatewayImpl.java

.../main/java/eu/teraflow/policy/context/ContextService.java

...n/java/eu/teraflow/policy/context/ContextServiceImpl.java

...rc/main/java/eu/teraflow/policy/context/model/Device.java

...n/java/eu/teraflow/policy/context/model/DeviceConfig.java

...va/eu/teraflow/policy/context/model/DeviceDriverEnum.java

...eraflow/policy/context/model/DeviceOperationalStatus.java

.../main/java/eu/teraflow/policy/context/model/EndPoint.java

src/policy/src/main/proto/context-policy.proto

...licy/src/test/java/eu/teraflow/policy/SerializerTest.java

.../generated-sources/grpc/context_policy/ContextPolicy.java

...ted-sources/grpc/context_policy/ContextPolicyService.java

...sources/grpc/context_policy/ContextPolicyServiceBean.java

...urces/grpc/context_policy/ContextPolicyServiceClient.java

...sources/grpc/context_policy/ContextPolicyServiceGrpc.java

...s/grpc/context_policy/MutinyContextPolicyServiceGrpc.java

src/policy/target/kubernetes/kubernetes.yml