Add ratatuefi (#358)

<!-- Thanks for making Ratatui awesome! 🐭 -->

* Link to your project (GitHub/crates.io):
<https://github.com/sermuns/ratatuefi>

* Description (optional): I didn't know until now
[ratatui-uefi](https://github.com/reubeno/tui-uefi) already existed...
this crate also provides a ratatui backend (also via `uefi` crate).

* Screenshot or gif (strongly recommended):
<https://github.com/user-attachments/assets/9c12cd86-6aef-4f9b-9006-e8e9d527dcc2>

<!--

### Tips 💡

* See how to release apps:
https://ratatui.rs/recipes/apps/release-your-app
* Share it in our Discord: https://discord.gg/DkvdWRPJ
* Share it in our Forum: https://forum.ratatui.rs/
* Add this badge to your README for showing off:

```md
[![Built With Ratatui](https://ratatui.rs/built-with-ratatui/badge.svg)](https://ratatui.rs/)
```

-->

Author: sermuns

README.md

@@ -43,6 +43,7 @@ Aside from those listed here, many other apps and libraries can be easily be fou
 - [dumo](https://github.com/iddey/dumo) - An embedded-graphics backend that is built on [mplusfonts](https://github.com/iddey/mplusfonts) and has kanji support.
 - [ratatui-minecraft](https://github.com/janTatesa/ratatui-minecraft) - A ratatui backend that uses [valence-screens](https://github.com/White-145/valence-screens)
 - [ratatui-uefi](https://github.com/reubeno/tui-uefi) - A ratatui backend for use in UEFI environments.
+- [ratatuefi](https://github.com/sermuns/ratatuefi) - Another library providing a ratatui backend for UEFI environments.
 - [ratatui-wgpu](https://github.com/Jesterhearts/ratatui-wgpu) - A wgpu based rendering backend for ratatui.
 - [ratzilla](https://github.com/orhun/ratzilla) - Build terminal-themed web applications with Ratatui and WebAssembly.
 - [rlt](https://crates.io/crates/rlt) - A universal load testing framework for Rust, with real-time tui support.