[Feature] Filter function based graph categories

[adrianlungu]

What problem does this feature solve?

This would help:

1. Allowing categories to not be bound by a single value from the node

If we want to define 2 or more legends that target different properties on the same graph, supporting a filter function instead of a specific predefined category field would allow us to select a specific field from the node for each category thus allowing more flexibility.

2. Allowing categories to target composite values

Using a filter function, we could build categories that depend on 2 or more properties of the node instead of being limited to 1.

What does the proposed API look like?

Something like this should work, and can also be implemented in a way that it is backwards compatible with the current API:

const categories = [
  {
    name: 'Main',
    filterFn: (node: any) => {
      return node.isMain
    },
  },
  {
    name: 'Error',
    filterFn: (node: any) => {
      return node.isError ?? false
    },
  },
]