feat (restful): Add /api/utils/refresh

The API call does the following:
- Fetch GitHub avatar and update artifact store url
- Revoke all cached resources

backend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "sub-store",
-  "version": "2.9.0",
+  "version": "2.10.0",
   "description": "Advanced Subscription Manager for QX, Loon, Surge, Stash and ShadowRocket.",
   "main": "src/main.js",
   "scripts": {