refactor: move catalogue logic into own package

catalogue/common.go

@@ -0,0 +1,17 @@
+package catalogue
+
+import (
+	"encoding/json"
+	"net/http"
+	"time"
+)
+
+func readJson(url string, target interface{}) error {
+	httpClient := &http.Client{Timeout: 5 * time.Second}
+	res, err := httpClient.Get(url)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	return json.NewDecoder(res.Body).Decode(target)
+}