Remove default shared layout

[niofire]

Remove the default navigation bar + footer from every page

[niofire]

There's a _Layout file which holds all of the shared layout. More info:

• https://docs.microsoft.com/en-us/aspnet/core/mvc/views/layout
• https://www.exceptionnotfound.net/asp-net-mvc-demystified-layout-viewstart-renderbody-and-rendersection/