This code generator no longer creates JS wrappers for platform objects
in the old sense, instead they're JS objects internally themselves.
Most of what we generate now are prototypes - which can be seen as
bindings for the internal C++ methods implementing getters, setters, and
methods - as well as object constructors, i.e. bindings for the internal
create_with_global_object() method.
Also tweak the naming of various CMake glue code existing around this.
To enable incremental movement towards the removal of DOM object
instance wrappers, this patch adds a NO_INSTANCE argument that can be
passed to libweb_js_wrapper().
