Agile Screen: live consumption tile add hint to data freshness

[ryanw-mobile]

Right now, the live consumption is reported in 10-second intervals.
Indeed, it is not absolutely "real-time".
We are also considering to fetch the data less frequently due to server traffic cap,
so it would be good to add an indicator to show how fresh the figure is.

[ryanw-mobile]

Tried a progress-bar style countdown, but since we now switched to show aggregated 1-minute live usage, the value shown is literally around 1 minute ago which is not so "live".

Therefore a more sensible presentation would be:

• Show the time stamp for which the consumption referres to.
• A green dot fading away in one second from green to grey - technically desaturates

So we can like refreshing the dot every one second without further animation.