Experimenting with more structured ways to handle command-line input/output in Rust

Implement `Localize` for `RelativeTime`

Moves the impl RelativeTime to use Localize directly rather than implicitly copying the interface.

Created by  finchie  on August 16, 2024
IRW6JACS3KVVA6HW5SBNBOHOQ2WRBHYGDND3FUWJYKJC7ZMOAVOQC
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