Make CertificateConfig linker friendly

[benaadams]

Currently can't use Certificates from config files if you link ASP.NET as all the setters for the config section are removed.

This directly references the properties rather than nebulously reflecting them via object so the linker will preserve them as they are directly used.

Resolves #25482

[benaadams]

@Tratcher any way to get this in for 5.0 (area-owners.md looks out of date so not sure who to ping); as certs are kinda common as is setting them via config?

Raised issue for the .Bind method in runtime dotnet/runtime#41658 however doesn't look like its an easy fix dotnet/runtime#40551

[Tratcher]

Comment that this is to preserve linkability.

[Tratcher]

It's plausible if you rebase this on release/5.0.

Is this the only bind in Kestrel config? I know bind is used extensively for other options types. Kestrel is already the odd one out for doing most of its own bindings.

Put another way, doesn't this linking issue with Bind cripple most Options types? Does fixing Kestrel really help make your app linkable if none of the other options types work?

[benaadams]

Is this the only bind in Kestrel config? I know bind is used extensively for other options types.

This particular Bind method is only used here and in IdentityServer.Configuration.KeyDefinition which I added another PR for #25487

https://source.dot.net/#Microsoft.Extensions.Configuration.Binder/ConfigurationBinder.cs,b3d80335ffffa242,references

[Tratcher]

Hmm, I guess the other bind calls I'm used to seeing are in the templates.

aspnetcore/src/ProjectTemplates/Web.ProjectTemplates/content/StarterWeb-CSharp/Startup.cs

Line 68 in 1bf292d

.AddAzureAD(options => Configuration.Bind("AzureAd", options));

Note these are moving in 5.0:

aspnetcore/src/ProjectTemplates/Web.ProjectTemplates/content/StarterWeb-CSharp/Startup.cs

Line 72 in 95c526f

.AddMicrosoftIdentityWebApp(Configuration.GetSection("AzureAd"))

To:
https://github.com/AzureAD/microsoft-identity-web/blob/eb8af9c1bd6dd0014420dd6d06fd4083bda1f8b9/src/Microsoft.Identity.Web/WebApiExtensions/MicrosoftIdentityWebApiAuthenticationBuilderExtensions.cs#L89

[benaadams]

Opened 5.0 targeted version #25493

Hmm, I guess the other bind calls I'm used to seeing are in the templates

Probably would need runtime fix in Configuration for that to recognise preserve the properties for the object's type that is passed in

[Tratcher]

If #25493 gets merged then we can close this PR, 5.0 auto merges forward to master.

[benaadams]

Superseded by #25515