remove nanex and nanocrawler backend options (both have shut down)

src/app/services/app-settings.service.ts

@@ -99,22 +99,6 @@ export class AppSettingsService {
       auth: null,
       shouldRandom: true,
     },
-    {
-      name: 'Nanex.cc',
-      value: 'nanex',
-      api: 'https://api.nanex.cc',
-      ws: null,
-      auth: null,
-      shouldRandom: false,
-    },
-    {
-      name: 'NanoCrawler',
-      value: 'nanocrawler',
-      api: 'https://vault.nanocrawler.cc/api/node-api',
-      ws: null,
-      auth: null,
-      shouldRandom: false,
-    },
     {
       name: 'Custom',
       value: 'custom',