Galician translation

Language ISO name: `gl`
Maintainer: nunhes
nunhes@gmail.com

Hi,
Galician is a language spoken primarily in Galicia, but with a historical presence that extends to the bordering regions of the northwestern Iberian Peninsula. It is the native language of nearly 2.5 million people in Galicia and thousands more in the Galician diaspora around the world, particularly in Latin America.

I have been dedicating myself to web development and training for several years. And I would like to contribute to this project by translating the content into my language: Galician.

此 issue 要求將教學課程翻譯成加利西亞語，但未指定檔案、測試或翻譯入口。首先檢查 repository 的貢獻與在地化結構，以確定翻譯範圍；完成的標準是，約定的教學課程內容已提供加利西亞語版本，並遵循專案的慣例。

由索引模型根據 Issue 內容生成。