[form] important refactoring of inlined forms to get proper separation of form object creation / rendering

__linkto may only appears in root form

[form] put unknown constructor args into extra_kwargs and consider them when looking for field display values

update to new file schema

forgotten that one

[form] replace is_subform by parent_form, carrying more information at the same cost

move low-level form handling to base form class

fix warning

rename form_build_context to build_context, and call it from form, not renderer

merge

[B] server: fix initial data structure in session.transaction_data

[form] make EntityFormRenderer a little bit easier to override

fix selectors

fix dumb name error

bad merge

backport stable

oops

merge

[ui api] backport create_links from forge so it may be reused

[schema] set composite on state_of / transition_of

cleanup not necessary

[fti] don't catch BaseException subclasses

support name metadata on guess_field; add name_field to FileField

[ui] turn footer items into actions

cleanup unused

use default repo looping task so they are started in thread, else we get blocking task

skel fixes

cleanup