[DOCS] Add docs for fable architecture and for contributors

[jkone27]

it would help possible contributors to have docs on fable architeture and how all works together,
exaple, now most relevant information is available in this video:

from https://www.youtube.com/watch?v=d6kfJnSIVUo

and

would be great to have a specific doc for all of those stages, describing what they are for, and how they play a role in the bigger fable architecture

• language x library (implementation)
• Transformer
• Printer

then projectCracker, pipeline, etc and other relevant components described one by one ..