Embedding a collection within a module?

You could add the individual actors to the module, which, assuming that they are in a common folder or filter, wouldn't be too hard to do.  Or you could insert the collection into a single artifact that is in the module. 

Yes adding individual actors wouldn't be too hard to do. However, these actors might be part of an evolving collection of actors. If I add the actors manually at a point of time, these list of actors might have evolved afterwards, and my module will not reflect this evolution.

< Or you could insert the collection into a single artifact that is in the module. 
Provided that RRM prevents me to add directly a collection to a module, I am assuming that you suggest to create an artifact (with text format I guess) into which I embed a collection, and that I add this single artifact into my module.
Is that correct?
I tested it and that works :) However, when I print the module, I get a simple list of all the artifacts that are part of my collection.
However, I wonder now if it is possible to embed in way or another a view of this collection with columns?

No, sorry, that is not possible.  Feel free to open an enhancement request if you don't find an existing one. 

I have a last complementary question, do you confirm it is not possible to embed a module within a module?
If this is true, then I'll add that as well to an enhancement request ( if there isn't an existing one )

correct, you cannot embed a module within a module.