Add appsetting.json to VENFT Blazor app

[fyziktom]

I have added the appsetting.json to the VENFT Blazor App. It is based on guidelines mentioned in #97 .

It is very simple.

• add appsetting.json to the wwwroot folder.
• add the using and inject settings
• get settings in components like this.

We should add the same settings in the VENFT OnePage #71 also.