feat(api.handlers.config): allow inheriting colors between projects

[dmyna]

Is your feature request related to a problem? Please describe.
If you have many subprojects and need to inherit a color for some interface rendered by fypm, you can't.
Ex:

color.project.Comput = rgb333

List some task that is in a Comput subproject (like Comput.Soft) and it will appear without color.

Describe alternatives you've considered
Specifying colors project by project.