Use gradient coloring scheme

[syamajala]

We should use a gradient based coloring scheme and have an option to color by different fields.

For example it should be selectable whether we want to color instances by size, lifetime, or maybe number of fields. Similarly for task boxes maybe you want to color by length or by instance size so you can see how much data they are accessing or by the total number of task launches.

The current coloring scheme should be the default but having these as options you could toggle would be nice.

Here is a library we could potentially use: https://github.com/mazznoer/colorgrad-rs