[actions box] enhance add related menu generation: don't propose to add relation of single cardinality where entity already have the relation set

[primary view] allow new 'subvid' parameter in primaryview_display_ctrl

[primary view] give dispctrl to side box views as for relations section

[web] unify list views call arguments: use subvid to specify the view to use for each item

[web] refactor side box to use autolimited view

[req] avoid getting w in cw_extra_kwargs when calling .view

[config] rename remaining inputlevel to level in option definitions, as expected by lgc >= 0.50

[fti] simplify UpdateFTIHook code

[twisted] we must set response code before starting to write the answer, else it's ignored

cleanup

[web data] remove files not used by the framework

[css] keep old css according to a configuration variable (true by default)

[3.8 execute] remove deprecation warnings

backport stable