Respect user's locale when rendering the date range in the repo activity page (#21410)
# Description
Previously, to make the date range understood by all, we used the format
"2006-01-02" for the dates as it's locale-generic.
This commit changes the rendering logic. Instead of rendering the date
on the server, we send a formatted computer-readable timestamp. The
client's javascript then renders it according to the user's locale.
This approach is reusable across the codebase, any `<time></time>` tag
with the data-format="date" attribute would get rendered according to
the user's chosen locale.
## Previous View

## New View
### English

### French

### Portuguese

### Italian

# References
* #21380
* #21387
* #21396
Inspiration:
I think either differentiating by class, or probably better by a custom
attribute such as `data-format` or similar, is the best course of
action.
_Originally posted by @delvh in
https://github.com/go-gitea/gitea/issues/21396#issuecomment-1274424788_
Resolves #21380
Signed-off-by: Yarden Shoham <hrsi88@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>