Date-only formatting directive

[jeff93063]

I would love to be able to use formulas on dates, without displaying the time. In addition to ;dt and ;hm, could we get a directive for just date by itself (I prefer YYYY-MM-DD but others use other formats)? Also formulas currently don't work with YYYY-MM-DD as an input, so that would need to be changed as well. Maybe the plugin could assume time 00:00 if no time is specified.

| Start      | End        | Elapsed  |
| ---------- | ---------- | -------- | 
| 2023-07-12 | 2023-07-13 |          | 
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Thank you very much.