Dashboard metrics

This is the PR for the dashboard/channel metric graphs
I'm not quite sure I understand the need for 2 loops here. Does the array need to ordered? If it doesn't need to be ordered you could do this using just a single loop.

Also, it seems you are adding an hour which is causing an tx that happens between 12:00 - 12:59 to be registered under 13:00. I think we should rather have these fall under 12:00 until the hour tick over.