Document how to use static web assets feature in all environments

[rynowak]

see: dotnet/aspnetcore#13190

We should make sure the docs include the difference between how this feature behaves in production vs development, and how to override this.

[javiercn]

We simply need to add a line to the docs that says

Static web assets are enabled by default during Development. If you want to explicitly support static web assets in other environments you can do so by calling
webHostBuilder.UseStaticWebAssets()

(Microsoft.AspNetCore.Hosting.WebHostBuilderExtensions.UseStaticWebAssets(this IWebHostBuilder builder))

[javiercn]

@guardrex Is this something we can get added to the RCL docs?

[akorchev]

Static web assets seem to work fine in production without explicitly invoking UseStaticWebAssets. Tested by running dotnet publish -c Release and then running the app itself via dotnet app.dll.

[javiercn]

@akorchev

The helper methods described above are only used when running the app from the build output (dotnet run) when the app gets published we simply copy the assets to their final destination and there is no additional runtime code required to make it work.

[javiercn]

@guardrex Can you also indicate that this is only required for non-published apps and that at publish time the assets are simply in their final locations?

[guardrex]

@javiercn Already done on the PR.

[javiercn]

Thanks! That was quick!