Retrieve the list of Helm charts via chart repo proxy endpoint

The reverse proxy obtained via httputil.NewSingleHostReverseProxy does not follow redirects,
and returns such requests to UI causing CORS issue, failing to load index.yaml from UI.

Our default repo redhat-developer.github.com redirects to redhat-developer.github.io and in order
to fix index.yaml loading, we started to use redhat-developer.github.io

frontend/public/components/catalog/catalog-page.tsx

@@ -334,13 +334,11 @@ export const Catalog = connectToFlags<CatalogProps>(
   }, [loadTemplates, namespace]);
 
   React.useEffect(() => {
-    coFetch('https://redhat-developer.github.io/redhat-helm-charts/index.yaml').then(
-      async (res) => {
-        const yaml = await res.text();
-        const json = safeLoad(yaml);
-        setHelmCharts(json.entries);
-      },
-    );
+    coFetch('/api/helm/charts/index.yaml').then(async (res) => {
+      const yaml = await res.text();
+      const json = safeLoad(yaml);
+      setHelmCharts(json.entries);
+    });
   }, []);
 
   const error = templateError || projectTemplateError;

pkg/helm/chartproxy/config.go

@@ -27,7 +27,7 @@ func RegisterFlags(fs *flag.FlagSet) *config {
 
 	cfg := new(config)
 
-	fs.StringVar(&cfg.repoUrl, "helm-chart-repo-url", "https://redhat-developer.github.com/redhat-helm-charts", "Helm chart repository URL")
+	fs.StringVar(&cfg.repoUrl, "helm-chart-repo-url", "https://redhat-developer.github.io/redhat-helm-charts", "Helm chart repository URL")
 	fs.StringVar(&cfg.repoCaFile, "helm-chart-repo-ca-file", "", "CA bundle for Helm chart repository.")
 
 	return cfg