Add .NET MAUI package to Installation section

[jfversluis]

Describe the feature that you would like added

Hi team! 👋

I'm Gerald Versluis from the .NET MAUI team. I've built a community NuGet package that brings Fluent UI System Icons to .NET MAUI: IconFont.Maui.FluentIcons.

Looking at your repo and amazing font it pains me that .NET MAUI is not on there, so I wanted to fix that. You don't even need to maintain it, it would just be great if you could link to it for discoverability :)

It uses the TTF font files from this repo directly and provides:

• Strongly-typed glyph constants generated at compile time from the TTF (via a Roslyn source generator)
• FontFamily constants that work with {x:Static} in XAML
• One-line registration: builder.UseIconFonts()
• Support for all font variations: Regular, Filled, Light, and Resizable

Usage

dotnet add package IconFont.Maui.FluentIcons

var builder = MauiApp.CreateBuilder()
    .UseMauiApp<App>()
    .UseIconFonts();

<Label Text="{x:Static icons:FluentIconsRegular.Home24}"
       FontFamily="{x:Static icons:FluentIconsRegular.FontFamily}" />

Proposal

Would you be open to adding a .NET MAUI section to the Installation part of the README? Something like:

### .NET MAUI

Install the community package:

```shell
dotnet add package IconFont.Maui.FluentIcons

For library docs, see IconFont.Maui.FluentIcons.

Happy to submit a PR if you're interested. The package source and the underlying source generator are both open source:
- 📦 [IconFont.Maui.FluentIcons](https://github.com/jfversluis/IconFont.Maui.FluentIcons)
- ⚙️ [IconFont.Maui.SourceGenerator](https://github.com/jfversluis/IconFont.Maui.SourceGenerator)

Thanks!

### Additional context

I see #391, #776 and #401 have been raised before but never finished.

If you would consider the FluentIcons package as an official package that would even be better, but also happy to leave it as a community one for now.

### Have you discussed this feature with our team

_No response_

### Validations

- [x] Check that there isn't already an issue that requests the same feature to avoid creating a duplicate.

### Priority

None