bricks/pybricks_qstrdefs.h: Only add used QSTRs.

This ensures we don't waste space with QSTRs that aren't used.

This makes the automation idea (see removed comment) optional.

bricks/pybricks_qstrdefs.h

@@ -1,16 +1,54 @@
 // qstrs specific to this port
 // *FORMAT-OFF*
-Q(Li-ion)
+
+#include "py/mpconfig.h"
+
 Q(stop button pressed)
-// TODO: Make these with makemoduledefs.py as it parses registered modules
+
+#if !PYBRICKS_HUB_MOVEHUB
+Q(Li-ion)
+#endif
+
+#if PYBRICKS_PY_EV3DEVICES
 Q(pybricks.ev3devices)
+#endif
+
+#if PYBRICKS_PY_EXPERIMENTAL
 Q(pybricks.experimental)
+#endif
+
+#if PYBRICKS_PY_GEOMETRY
 Q(pybricks.geometry)
+#endif
+
+#if PYBRICKS_PY_HUBS
 Q(pybricks.hubs)
+#endif
+
+#if PYBRICKS_PY_IODEVICES
 Q(pybricks.iodevices)
+#endif
+
+#if PYBRICKS_PY_MEDIA
 Q(pybricks.media)
+#endif
+
+#if PYBRICKS_PY_NXTDEVICES
 Q(pybricks.nxtdevices)
+#endif
+
+#if PYBRICKS_PY_PARAMETERS
 Q(pybricks.parameters)
+#endif
+
+#if PYBRICKS_PY_PUPDEVICES
 Q(pybricks.pupdevices)
+#endif
+
+#if PYBRICKS_PY_ROBOTICS
 Q(pybricks.robotics)
+#endif
+
+#if PYBRICKS_PY_TOOLS
 Q(pybricks.tools)
+#endif