Port QLocale on MS away from the use of LCID; use names instead

According to MS's own docs the use of LCID locale identifiers is now deprecated in favour of using locale names.
This should make the code cleaner.

Furthermore, we have a table (provenance undocumented, from 2004, for Win '95) mapping LCIDs to locale names embedded in qlocale_win.cpp, that's used in the implementations of qt_inIsoNametoLCID()}, used by {{qcollator_win.cpp, and of qt_localeFromLCID(), used by qwindowsinputcontext.cpp (and a commented-out line of code in qwindowskeymapper.cpp). The callers of these should be ported away from LCIDs at the same time (and a large pile of scarily old code can then be deleted).
Relevant bits of qlocale_win.cpp, as dependency tree:

• WindowsToISOListElt
  • ByWindowsCode
  • windows_to_iso_list[]
    • extern qt_inIsoNametoLCID()
      • ⇒ qcollator_win.cpp
    • winLangCodeToIsoName()
      • getWinLocaleName()
        • extern qt_localeFromLCID()
          • ⇒ qwindowsinputcontext.cpp
          • // qwindowskeymapper.cpp