logilab-astng #77253 provide a way for user code to register astng "transformers" [validation pending]

eg arbitrary code that will be called with module nodes that have been freshly built.

This should provide room to do application specific stuff that can't currently be inferenced.

prioritynormal
typeenhancement
done in0.23.0
load0.100
load left0.000
closed by#e35543060167 closes #77253: provide a way for user code to register astng transformers