Integrate QUrl's IDNA code with our Unicode character database

In qtbase/src/corelib/io/qurlidna.cpp I find a table and several functions that hard-code Unicode code-points and transformations that should surely be generated from the Unicode character database (UCD), which we incorporate in qtbase/src/corelib/text/qunicodetables.cpp and its private header; this data is generated by a program in qtbase/util/unicode/, which may need an update to include (up to date) IDNA data tables with the ones we already get from the UCD.

The hard-coded data in QUrl's IDNA code is not updated as part of our UCD updates; I infer that it is probably out of date. It includes bidirectional text query functions and a case-folding data table. These are surely relevant elsewhere and likely (aside from probably being out of date) duplicate data in corelib/text/'s unicode tables.