Colors in inheritance graphs: supported/mature, in development, abadoned

Inheritance graphs: the loop that generates the graphs should read an ATTRIBUTE from a class to mark {green : supported/mature, yellow : in development, red : abadoned, no-color: unknown}. So we have colors in the inheritance graphs and it's quick to see the status of classes in code.

Two new attributes in classes

1. supportStatus: {green : supported/mature, yellow : in development, red : abadoned, no-color: unknown}, an enum
2. publication: string with authors and the paper

This is going to replace the wiki page: https://yade-dem.org/wiki/ConstitutiveLaws

I started working on this in branch https://gitlab.com/yade-dev/trunk/-/commits/supportStatus but it's a draft.