cubicweb #2443038 synchronous tabs [validation pending]

currently tabs are lazy by design. In some cases it may be desired or necessary to have synchronous tabs, for instance when tabs hold forms posting to themselves. A simple 'lazy' class boolean flag should control that behaviour

prioritynormal
typeenhancement
done in3.15.3
load0.100
load left0.000
closed by#5161573ba806 [tabbed view] make tabs optionaly lazy: lazy=False on the tabbed view trigger synchronous tabs. Closes #2443038