Improve API4 initialization (#18680)

* Improve API4 initialization

- Refactored openGraphDataCache to be inside app layer.
- Moved the cache instance from global variable to be inside server.
- Moved out the app instantiation from the global commands package
to be instantiated on every call. Only the server instance is passed.
- Moved InitLocal to be called from inside Init.

```release-note
NONE
```

* Remove commented line

```release-note
NONE
```

web/web_test.go

@@ -122,7 +122,7 @@ func setupTestHelper(tb testing.TB, includeCacheLayer bool) *TestHelper {
 	ctx := &request.Context{}
 	a := app.New(app.ServerConnector(s.Channels()))
 
-	web := New(a, s.Router)
+	web := New(s)
 	URL = fmt.Sprintf("http://localhost:%v", s.ListenAddr.Port)
 	apiClient = model.NewAPIv4Client(URL)