The old approach required adding a special virtual field
to any table potentially needing such foreign-id pagination and
also still required manually sorting according to pagiantion settings
since the pagination helper does not know whether
this virtual field was set or not.
Using lists with each entry containing the pagination id and the actual
entry insterad allows any table to use this mechanism unchanged and
does not require manually sorting.
Since it was unused, this also drops the pagination mode paramter from
fetch_favourited_with_fav_id.
Furthermore, as a side effect of this change a bug in the favourite
benchmark is fixed. It used to incorrectly attempt to use IDs of
the liked objects for pagination instead of the like IDs as advertised
in Link headers.
Ecto.cast is will convert valid string keys to atoms, but can
only deal with inputs which use either string keys everywhere
or atom keys everywhere.
Since :id_type is used before the case it must be an atom,
thus it was impossible to use it with string paramteres before.
Up until now queries were always forced into descending ID order
(reverse chronological order with our ID schemes).
Now it’s possible to request the reverse by passing `oder_asc: true`.
Atom keys could also have been transformed to string, or the other
way around but this one is more efficient and what we actually
expect with the current param_types in Pagination
