Plan independent BFF and adapt selected Sendico foundations (#34)

Makefile

@@ -8,3 +8,15 @@ test-frontend:
 	cd frontend/packages/sxchnge_theme && flutter test
 	cd frontend/packages/sxchnge_theme/example && flutter test
 	cd frontend/app && flutter test
+
+.PHONY: test-backend lint-backend run-backend
+
+test-backend:
+	cd backend && go test -race ./...
+
+lint-backend:
+	cd backend && test -z "$$(gofmt -l .)"
+	cd backend && go vet ./...
+
+run-backend:
+	cd backend && go run ./cmd/bff