Time format less resources

[neilboyd]

This PR is a work in progress. Comments are welcome to help guide the progress.

Use double formatting as suggested in #571 (comment) in order to reduce the number of translated string resources needed for #1183

Put this on hold because there's a lot more to do, and maybe it's not even helping for #1183, so I'll get back to that.

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[neilboyd]

I will not do this as a predecessor to #1183. Could still do it afterwards, but that's another story.