Document features

Sentry docs doesn't document the SDK features like:

Incomplete list follows:

## Main Sentry SDK (all .NET apps):

### Captures automatically:
* [Unhandled Exceptions](https://docs.microsoft.com/en-us/dotnet/api/system.appdomain.unhandledexception)
* [Unobserved Task Exceptions](https://docs.microsoft.com/en-us/dotnet/api/system.threading.tasks.taskscheduler.unobservedtaskexception)

### Other features

* Submits events on the background
* Events sent are compressed
* Deduplicates errors (same exception rethrown is logged once)
* Flushes events on [`ProcessExit`](https://docs.microsoft.com/en-us/dotnet/api/system.appdomain.processexit)
* Accepts filtering exceptions by Exception Type `AddExceptionFilterForType`.
* Includes a debug mode to see the SDK logs
* Includes list of .NET Framework versions installed
* Keeps events on disk when device is offline
* If opt-in `SendDefaultPii`, reports the username `Environment.UserName`
* Includes runtime information like .NET Core, Mono and version

### ASP.NET Core

* Automatically tracks all logs for the request and includes as breadcrumb
* Customize logic to create the Sentry User
* Customize things via DI

### ASP.NET and ASP.NET Core

* Includes request data like headers, URL
* Includes server name and other server data
* If opt-in, includes the request body sent to the server