[libcalamares] Allow retrieving chroot mode from system (as well as settings)

src/libcalamares/utils/CalamaresUtilsSystem.cpp

@@ -256,5 +256,10 @@ System::getTotalMemoryB()
 #endif
 }
 
-
+bool
+System::doChroot() const
+{
+    return m_doChroot;
 }
+
+}  // namespace

src/libcalamares/utils/CalamaresUtilsSystem.h

@@ -114,6 +114,8 @@ public:
      */
     DLLEXPORT QPair<quint64, float> getTotalMemoryB();
 
+    DLLEXPORT bool doChroot() const;
+
 private:
     static System* s_instance;