Add ITU-D identifiers to tests

[ronaldtse]

The list of ITU-D Recommendations are here:

• https://www.itu.int/rec/D-REC-D/en

The full list of ITU-D publications are here:

• https://www.itu.int/en/ITU-D/Pages/itu-d-publications.aspx

However they don't really have visible identifiers, except that their URLs look like this:

• https://www.itu.int/hub/publication/d-phcb-conn_pol-2023-01/

I assume that d-phcb-conn_pol-2023-01 is its identifier.