Terminolgy Change: "Playspace" -> "Room"

Valve's official terminology are "Room Setup" and "Tracking Universe". Changed our usage of "Playspace" to "Room" for clarity with the upcoming Room-Turn feature and existing Room-Drag feature when compared to nomenclature for other tools that exits out there.

Also slight clean up in readability of movecentertab's action functions.

src/tabcontrollers/FixFloorTabController.cpp

@@ -145,7 +145,7 @@ void FixFloorTabController::eventLoopTick(
                 floorOffsetZ = tempOffsetZ;
 
                 LOG( INFO )
-                    << "Fix Floor and adjust playspace center: Floor Offset = ["
+                    << "Fix Floor and adjust room center: Floor Offset = ["
                     << floorOffsetX << ", " << floorOffsetY << ", "
                     << floorOffsetZ << "]";
                 float offset[3] = { 0, 0, 0 };