Without this change, "source/a/b" in non-strict mode indexes:
  (document.uid, source.uid, b.uid, 1)
  (document.uid, source.uid, a.uid, 0)
  (document.uid, source.uid, source.uid, 0)
This last line does not contain anything which cannot be found by looking
at the base category uid column, so it is wasting disk (and index) space,
costing performance.
But keep indexing a Base Category document if is it not the base category
for considered relation. It is not clear whether stopping indexation at the
first encountered Base Category document is intentional, or if recursion
should only stop when reaching the base category of considered relation.
With this change, "source/a/b" in non-strict mode indexes:
  (document.uid, source.uid, b.uid, 1)
  (document.uid, source.uid, a.uid, 0)
removing the redundancy.

It is overkill, and is likely slower than just passing the needed
values straight to catalog.
Also, rely on duck-typing instad of portal-type-testing.
Also, drop unused "spec" and "filter" arguments.
Also, expose strict{,_membership} used arguments, simplifying code.
Keep catchall **kw for compatibility.

erp5_travel_expense: Add transactions view on Expense Validation, Fix/Update  transaction generation

erp5_travel_expense: avoid undefined value

erp5_travel_expense: link related to Travel Request instead of record

erp5_travel_expense: can use listbox to search related mission in expense record

This was only used by listbox.
As most fields now render themself as 'p' tag in non editable mode, they are compatible with non editable listboxes to be rendered inside an 'a' tag.