core&ui: add setting provider

packages/hydrooj/src/handler/home.ts

@@ -146,7 +146,7 @@ export class HomeHandler extends Handler {
     }
 
     async get({ domainId }) {
-        const homepageConfig = this.domain.homepage || system.get('hydrooj.homepage');
+        const homepageConfig = this.ctx.setting.get('hydrooj.homepage');
         const info = yaml.load(homepageConfig) as any;
         const contents = [];
         for (const column of info) {