Add simple simulator stub.

plugins/quantum_computing/src/circuit_elements/QuantumCircuitElement.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <memory>
+
+class QuantumCircuitElement
+{
+public:
+    enum class Type
+    {
+        INPUT_TERMINAL,
+        OUTPUT_TERMINAL,
+        WIRE,
+        GATE,
+        UNKNOWN
+    };
+
+    virtual ~QuantumCircuitElement() = default;
+
+    virtual bool isFullyConnected() const = 0;
+
+    virtual QuantumCircuitElement::Type getType() const = 0;
+};