MAUI Android Background Task Documentation missing

### Description

Since there is https://github.com/dotnet/maui/issues/19041 for iOS, I wanted to ask how background service in an app would run in MAUI for Android.

My tries so far.

1. Add the `Microsoft.Extensions.Hosting` NuGet package and try to run it as `BackgroundService` as for ASP.Net (As described here https://learn.microsoft.com/en-US/dotnet/architecture/microservices/multi-container-microservice-net-applications/background-tasks-with-ihostedservice), e.g.

```csharp
builder.Services.AddSingleton();
builder.Services.AddHostedService(p => p.GetRequiredService());
```

--> Doesn't work, service is never executed. :collision:

2. Implement it as it was done in Xamarin like described in https://learn.microsoft.com/en-us/previous-versions/xamarin/android/app-fundamentals/services/creating-a-service/.

--> Doesn't work, the `[Service]` attribute and the `Service` class do not exist. :collision:

3. Following https://github.com/dotnet/maui/issues/20678 and https://github.com/alzubitariq/MauiAppServiceIssue, I tried to add the service as following:

```csharp
#if ANDROID
builder.Services.AddSingleton();
#endif
```

and implemented the service like this:

```csharp
public interface IDataQueueService
{
Task Start();
Task Stop();
}
```

and

```csharp
public sealed class DataQueueService : IDataQueueService
{
private readonly CancellationTokenSource cancellationTokenSource = new();

public Task Start()
{
_ = this.Execute();
return Task.CompletedTask;
}

public Task Stop()
{
this.cancellationTokenSource.Cancel();
return Task.CompletedTask;
}

private async Task Execute()
{
while (!this.cancellationTokenSource.IsCancellationRequested)
{
// Todo: Something more useful here.
Console.WriteLine("Mane");
await Task.Delay(5000);
}

// Todo: Something more useful here.
Console.WriteLine("Mane2");
}
}
```

and in the `MainPage.xaml.cs` in the constructor:

```csharp
public MainPage()
{
this.InitializeComponent();

#if ANDROID
var services = Application.Current?.MainPage?.Handler?.MauiContext?.Services;

if (services is not null)
{
var backgroundService = services.GetService();

if (backgroundService is not null)
{
backgroundService.Start();
}
}
#endif
}
```

--> Seems to work, but not sure if background services should be used like this. 😕

Any advice / documentation on how to do this with MAUI on Android would be nice.

### Steps to Reproduce

Check above.

### Link to public reproduction project repository

_No response_

### Version with bug

8.0.40 SR5

### Is this a regression from previous behavior?

Not sure, did not test other versions

### Last version that worked well

Unknown/Other

### Affected platforms

Android

### Affected platform versions

_No response_

### Did you find any workaround?

Solution 3 seems to work, but not sure if this i correct. + This should get documented somewhere...

### Relevant log output

```shell
wasm-tools 8.0.5/8.0.100 VS 17.9.34902.65
ios 17.2.8004/8.0.100 VS 17.9.34902.65
maui-windows 8.0.7/8.0.100 VS 17.9.34902.65
android 34.0.52/8.0.100 VS 17.9.34902.65
maccatalyst 17.2.8004/8.0.100 VS 17.9.34902.65
```