Fix the Linux build of the qt6 branch, compile QML to bytecode only

- Remove Core5Compat (unused, not part of the Steam Frame's system Qt).
- Request GuiPrivate explicitly (required since Qt 6.10 for QRhi); temporary
  until rendering moves to public API.
- Compile QML to bytecode only: C++ generated from QML uses private Qt API
  that only matches the exact Qt version it was built with.
- Pick the OpenVR library per architecture (linux64, linuxarm64, win64) for
  linking and for the copy next to the binary; RPATH $ORIGIN.
- Link libXtst, needed by input_sender_X11.cpp.
- Include d3d11.h and handle QRhi::D3D11 only on Windows.
- Replace leftover easylogging LOG(INFO) calls with qInfo().

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/tabcontrollers/MoveCenterTabController.cpp

@@ -1109,7 +1109,8 @@ void MoveCenterTabController::zeroOffsets()
                     parent->m_chaperoneTabController.createNewAutosaveProfile();
                     m_initComplete = true;
                     m_chaperoneBasisAcquired = true;
-                    LOG( INFO ) << "Chaperone Initilization Complete, Space Drag Now Enabled";
+                    qInfo() << "Chaperone Initilization Complete, Space Drag "
+                               "Now Enabled";
                 }
             //}
             // else