[views] simplify and fix the TreeView (closes #16055814)
Simplify the (internal) TreeView._init_params() method to get rid of the
useless 'initial_thru_ajax' argument.
The ajax tree view was not working properly when loaded via ajax, for
instance from a lazy tab. This was due to the buggy protection against
double javascript/ css inclusion, which is no more needed server-side as
it is now implemented client-side.
Deprecate use of the initial_thru_ajax argument of the TreeView.call() method.
usr/lib/python2*/*-packages/cubicweb/etwist/