Add warning for long durnation of max CPU usage on powersave

[Shuzhengz]

Is your feature request related to a problem? Please describe.
Adds a warning (in monitor perhaps) for long durnation of max CPU usage for one of the cores when in powersave mode, so that it could notify the user when a process is stuck (like let's say a webpage that does not stop loading) and potentially draining the battery

Describe alternatives you've considered
Keeping an eye on CPU usage manually

Additional context
My battery died in a lab because canvas keeps loading forever and I didn't notice :(

[JakeRoggenbuck]

We could also predict battery life. I could see these two features working well together.

[Shuzhengz]

Mb we can also add a graph for predicted battery life