feat: Introduce locale package and add Arabic (ar_SA) translation.

[mhndm]

Adding Arabic lang

[fguillot]

The unit tests are not passing. There are few issues regarding the plural translations.

There are 6 plural forms for the Arabic language according to https://docs.translatehouse.org/projects/localization-guide/en/latest/l10n/pluralforms.html

nplurals=6; plural=(n==0 ? 0 : n==1 ? 1 : n==2 ? 2 : n%100>=3 && n%100<=10 ? 3 : n%100>=11 ? 4 : 5);