[Package Request] Ruby

[tsutsu]

We already had a Ruby package, but we removed it after #1844 (Synology began to distribute their own first-party Ruby package.)

But in June of 2020, Synology EOLed their Ruby package, and removed it from their package source.

Can we "un-retire" the Ruby package, and get it building again?

(I'm guessing I don't need to follow the package-request format here — we already have the Ruby package spec in commit history, viewable as of its deletion in 799f368.)

[hgy59]

I have this in focus for #2178