build: qt: split locale resources. Fixes non-deterministic distcheck

The rcc tool is quirky and only honors files in the same directory as the qrc.
When doing an out-of-tree build (as 'make distcheck' does), the generated
translation files end up in a different path, so rcc can't find them.

Split them up so that rcc is run twice: once for static source files and once
for generated files.