Added Irish/Gaeilge translation

This merge request adds a full Irish (ga) translation for the Nala package manager. I based my work on the nala.pot template file to ensure consistency with the original English source strings.

All translations were created and reviewed using Poedit, and no errors or formatting issues were flagged during validation.

Please note that I used the general Irish language code ga, rather than a region-specific variant like ga_IE.

Let me know if you need anything else from my side!

Go raibh maith agaibh, Aindriú Mac Giolla Eoin