Removed docs for ASP.NET 3.x and added caveat for ASP.NET 2.3 support (#16534)

## DESCRIBE YOUR PR

Resolves getsentry/sentry-dotnet#4904
- getsentry/sentry-dotnet#4904

## IS YOUR CHANGE URGENT?  

- [ ] None: Not urgent, can wait up to 1 week+

## SLA

- Teamwork makes the dream work, so please add a reviewer to your PRs.

cc: @Flash0ver 

## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [ ] Checked Vercel preview for correctness, including links
- [ ] PR was reviewed and approved by any necessary SMEs (subject matter
experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs
team](https://github.com/orgs/getsentry/teams/docs)

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Stefan Pölz <38893694+Flash0ver@users.noreply.github.com>
Co-authored-by: Johannes Daxböck <johannes.daxboeck@sentry.io>

Author: 4 people

platform-includes/configuration/config-intro/dotnet.aspnetcore.mdx

@@ -1,7 +1,7 @@
 Options can be set by passing a callback to the `UseSentry()` method which will
 pass the option object along for modifications:
 
-ASP.NET Core 6.0+:
+### ASP.NET Core 6.0+:
 
 ```csharp
 var builder = WebApplication.CreateBuilder(args);
@@ -25,39 +25,9 @@ builder.WebHost.UseSentry(fun o ->
             ) |> ignore
 ```
 
-ASP.NET Core 3.0:
+### ASP.NET Core 2.3 on .NET Framework:
 
-```csharp
-public static IHostBuilder CreateHostBuilder(string[] args) =>
-    Host.CreateDefaultBuilder(args)
-        .ConfigureWebHostDefaults(webBuilder =>
-        {
-            // Add the following line:
-            webBuilder.UseSentry(o =>
-            {
-                o.Dsn = "___PUBLIC_DSN___";
-                o.MaxBreadcrumbs = 50;
-                o.Debug = true;
-                o.SendDefaultPii = true;
-            });
-        });
-```
-
-```fsharp
-let CreateHostBuilder args =
-    Host.CreateDefaultBuilder(args)
-        .ConfigureWebHostDefaults(fun webBuilder ->
-            // Add the following line:
-            webBuilder.UseSentry(fun o ->
-                o.Dsn <- "___PUBLIC_DSN___"
-                o.MaxBreadcrumbs <- 50
-                o.Debug <- true
-                o.SendDefaultPii <- true
-            ) |> ignore
-        )
-```
-
-ASP.NET Core 2.x:
+Although ASP.NET Core 2 is no longer supported for .NET Core, Microsoft maintain ASP.NET Core 2.3 to make it easier for people using .NET Framework to transition to ASP.NET Core. If you are using [ASP.NET Core 2.3 on .NET Framework](https://dotnet.microsoft.com/platform/support/policy/aspnet#dotnet-core) then you can configure Sentry using the `WebHostBuilder`:
 
 ```csharp
 public static IWebHost BuildWebHost(string[] args) =>

platform-includes/getting-started-config/dotnet.aspnetcore.mdx

@@ -1,6 +1,6 @@
 Add Sentry to `Program.cs` through the `WebApplicationBuilder`:
 
-ASP.NET Core 6.0+:
+### ASP.NET Core 6.0+:
 
 ```csharp
 var builder = WebApplication.CreateBuilder(args);
@@ -14,28 +14,9 @@ let builder = WebApplication.CreateBuilder(args)
 builder.WebHost.UseSentry("___PUBLIC_DSN___") |> ignore
 ```
 
-ASP.NET Core 3.0:
+### ASP.NET Core 2.3 on .NET Framework:
 
-```csharp
-public static IHostBuilder CreateHostBuilder(string[] args) =>
-    Host.CreateDefaultBuilder(args)
-        .ConfigureWebHostDefaults(webBuilder =>
-        {
-            // Add the following line:
-            webBuilder.UseSentry("___PUBLIC_DSN___");
-        });
-```
-
-```fsharp
-let CreateHostBuilder args =
-    Host.CreateDefaultBuilder(args)
-        .ConfigureWebHostDefaults(fun webBuilder ->
-            // Add the following line:
-            webBuilder.UseSentry("___PUBLIC_DSN___") |> ignore
-        )
-```
-
-ASP.NET Core 2.x:
+Although ASP.NET Core 2 is no longer supported for .NET Core, Microsoft maintain ASP.NET Core 2.3 to make it easier for people using .NET Framework to transition to ASP.NET Core. If you are using [ASP.NET Core 2.3 on .NET Framework](https://dotnet.microsoft.com/platform/support/policy/aspnet#dotnet-core) then you can configure Sentry using the `WebHostBuilder`:
 
 ```csharp
 public static IWebHost BuildWebHost(string[] args) =>