Show "Just updated" or "Updated X ago" on top

[WhyNotHugo]

@WhyNotHugo said:

FWIW, the top date could actually read "Just updated" and then "Updated X Y ago", where Y in ["minute", "hours", "days"] and X is an int.

@mhmdanas said:

[...] it makes it easier to know at a glance if the weather is outdated. On the other hand, we will have to handle updating the time, though it shouldn't be too much trouble.