GitLab

Basically a refactoring of the whole module to simplify it a lot removing the never used overkill DeprecationManager class and move to just a list of simple function.

I've backported from DeprecationManager the principle of displaying the module in which the warning is fired by making it automatic using frame walking.

Also, as discussed with Nicolas, we should probably extract this from logilab-common into a new standalone python module like most of the modules of logilab-common, having everything bundle doesn't make that much sens anymore.