Add containers project with CMake setup and array-related functionality

- Implement `printArrayAtPosition` in `functions.cpp` with input validation.
- Created `main.cpp` to demonstrate array operations using C arrays and `std::vector`.
- Updated `ClassA` and `IComparable` with constructors, destructors, and deep copy logic.
- Adjusted IntelliJ project configuration for new containers module.

cpp/containers/functions.h

@@ -0,0 +1,10 @@
+//
+// Created by David Hackbarth on 20.02.26.
+//
+
+#ifndef CONTAINERS_FUNCTIONS_H
+#define CONTAINERS_FUNCTIONS_H
+
+void printArrayAtPosition(int* array, int position);
+
+#endif //CONTAINERS_FUNCTIONS_H