WIP: Restructing auth api and service

Signed-off-by: Asai Neko <sugar@sne.moe>

service/service_auth/service.go

@@ -0,0 +1,12 @@
+package service_auth
+
+type AuthService interface {
+	Exchange(*ExchangePayload) *ExchangeResult
+	Magic(*MagicPayload) *MagicResult
+}
+
+type AuthServiceImpl struct{}
+
+func NewAuthService() AuthService {
+	return &AuthServiceImpl{}
+}