This allows using all the libnumbertext library functions.

[NatNum12] gives cardinal number names (one, two, three, ...)
[NatNum12 ordinal] gives ordinal number names (first, second, third, ...)
[NatNum12 ordinal-number] gives ordinal indicators (1st, 2nd, 3rd, ...)
[NatNum12 money USD][$-409] gives formal English (US) money text
... etc (see numbertext.org for syntax).

Change-Id: I16dbb44d8d4bdb82a1b950de6d438c8311b554ff
Reviewed-on: https://gerrit.libreoffice.org/54366Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: László Németh <nemeth@numbertext.org>