Use generator to generate exceptions from yaml

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

internal/exception/service_gen.go

@@ -0,0 +1,8 @@
+// Code generated by gen-exception; DO NOT EDIT.
+package exception
+
+const (
+	ServiceUser = "002"
+	ServiceEvent = "003"
+	ServiceAuth = "001"
+)