DateTime
There was a question about "how to improve the datetime display for SSH/PGP/WebAuthn" https://github.com/go-gitea/gitea/pull/28262#issuecomment-1831141611 The root problem is that `DateTime` misses the "data-tooltip-content" attribute, which should be used to make the tooltip popup smoothly. Now the UI is consistent and the end users could see the detailed hour/minute/second easily by hovering the element.  
