add PIString::lineNumber() method

add ""_tr literal to translate string by PITranslator
add pip_tr util, now useless, only can generate *.ts
add qt_support internal lib, now only works with *.ts file
pip_vtt migrate to qt_support

utils/qt_support/CMakeLists.txt

@@ -0,0 +1,4 @@
+file(GLOB SRC "*.h" "*.cpp")
+add_library(pip_qt_support STATIC ${SRC})
+target_include_directories(pip_qt_support PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
+target_link_libraries(pip_qt_support pip)