Add Arabic translation

[mstfelg]

Thank you for this handy app.

[forrestguice]

Thanks for the contribution. ❤️
I will review/merge this later today, and then tag v0.15.14 over the weekend.
It should be on F-Droid sometime next week.

[forrestguice]

I've reviewed this and made a few minor fixes. This looks good. 👍

There is one problem remaining though - lint complains that ar requires a complete set of plurals (zero, one, two, few, many, other). This can be a little confusing since each locale has its own rules (e.g. many locales only need one and many), or they use the rules in peculiar ways (e.g. I think Russian uses the one rule for any value that contain a 1).

Anyhow, I'm not certain what the rules are for Arabic , so I've added untranslated lines for those values (now marked TODO).
I'll leave this open a few more days before merging (if you want to amend it).

Once the translation is published, it can be update whenever you'd like, and I'll tag another patch version (on a 2-3 week cycle).