AUTH-2588 add DoH to service mode

overwatch/manager.go

@@ -0,0 +1,17 @@
+package overwatch
+
+// Service is the required functions for an object to be managed by the overwatch Manager
+type Service interface {
+	Name() string
+	Type() string
+	Hash() string
+	Shutdown()
+	Run() error
+}
+
+// Manager is based type to manage running services
+type Manager interface {
+	Add(Service)
+	Remove(string)
+	Services() []Service
+}