cubicweb-container #2556286 make the two hooks abstract [resolved]

Better make them concrete and set their selector in client cubes. Hence, an app. made from several container-using-cubes won't lose the __select__ monkeypatch war.

prioritynormal
typeenhancement
done in1.0.0
load0.100
load left0.000
closed by#0bc0cd975c24 [hooks] base hooks are abstract (closes #2556286)