Configurable warn and error levels for used rastertime

[micheldebree]

Is your feature request related to a problem? Please describe.
I have certain limits regarding rastertime. One way to keep an eye on the rastertime is in the flight recorder.
Rasterlines 0x10 and above make numbers and the peaks in the graph turn orange, and x 0x18 and above turns red
These numbers are hardcoded and I would like to be able to adjust them to my needs.

Describe the solution you'd like
Two new config parameters for warning and error level rastertime use, with defaults described as above

Describe alternatives you've considered
Keeping an eye on the SL column in the flight recorder

Additional context
A further improvement could be to keep track of the max rastertime used and print that