Add new heatmap node display

[cRui861]

Is your feature request related to a problem? Please describe.
Display for running state is difficult to read with multiple nodes.

Describe the solution you'd like
Use a gradient of different colors for each percentage bucket of running state. (e.g. 0-25% would be a light green and 25-50% would be a semi-light green but a little darker, etc)

[cRui861]

Fixed #2497