Add support for split modules in alignment

Following ATLIDTRKCP-519. Add use of (already implemented) addSplitAlignment so that ITk Strip modules which are split into multiple readout elements can have those elements sharing an AlignableTransform (the individual readout elements being part of the same silicon wafer, meaning they are physically bound together and should not be aligned with respect to one another).

This could also be used for any other case where the readout elements are not individually alignable.

FYI @xilin @sroe @pbruckma

GeoModelTools/GeoModelXML/GeoModelXml/src/GmxInterface.cxx

@@ -67,7 +67,7 @@ void GmxInterface::addSensor(const string& name, map<string, int> &index, int se
 
 void GmxInterface::addSplitSensor(const string& name, map<string, int> &index, std::pair<std::string, int> &extraIndex, int sequentialId, GeoVFullPhysVol *fpv,int splitLevel) {
     std::stringstream idString;
-    msglog << MSG::DEBUG << "GmxInterface::addSensor called for " << fpv->getLogVol()->getName() << ", type " << name << 
+    msglog << MSG::DEBUG << "GmxInterface::addSplitSensor called for " << fpv->getLogVol()->getName() << ", type " << name << 
                          ". Indices:   ";		
     for (map<string, int>::iterator i = index.begin(); i != index.end(); ++i) {
         msglog << i->second << "   ";
@@ -111,7 +111,7 @@ void GmxInterface::addSplitAlignable(int level, map<std::string, int> &index, st
     std::stringstream idString;
     // debug message
     msglog << MSG::DEBUG 
-        << "GmxInterface::addAlignable called for a physvol. Logvol name " 
+        << "GmxInterface::addSplitAlignable called for a physvol. Logvol name " 
         << fpv->getLogVol()->getName() << ". Level = " << level << ". Indices:   ";
     for (map<string, int>::iterator i = index.begin(); i != index.end(); ++i) {
         msglog << i->second << "   ";