Integrate Calypso Packages in Pharo

[guillep]

We need to put Calypso packages inside the Pharo repository.
We need that this is not optimal but the alternative to it (editing calypso in a separate repository) creates a ripple of effect of releases (tagging, changing baseline, PR, integration).
The objective is to ease updates to calypso's cross cutting aspects (Rubric usage, refactorings...).

Eventually this should be managed by subprojects/submodules/subtrees but the solution is not there yet.