This makes three big changes to how translation files are generated:
- use Qt5 cmake built-in commands to do the translations rather than
calling lrelease directly. lrelease is often not in the path, while Qt5
cmake knows how to find and invoke it.
- Slam the resulting files into a C++ file using a cmake script rather
than needing to compile a .c file to generate C++ file. This is
simpler, but more importantly avoids the mess needed when cross
compiling of having to import a cmake script from an external native
build.
- In the actual generated files, use an unordered_map rather than a
massive list of static variable pointers.
