Add additional circuit example for direct OpenQASM import

doc/source/tutorials/includes/circuits/circuits1.qasm

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+// Generated by QIBO 0.2.4
+OPENQASM 2.0;
+include "qelib1.inc";
+qreg q[3];
+creg a[2];
+cz q[0],q[2];
+gpi2(0.3) q[1];
+cz q[1],q[2];
+measure q[0] -> a[0];
+measure q[2] -> a[1];

doc/source/tutorials/includes/circuits/circuits2.py

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+import matplotlib.pyplot as plt
+import numpy as np
+
+from qibolab import execute_qasm
+
+# define the circuit in OpenQASM
+circuit = """// Generated by QIBO 0.2.4
+OPENQASM 2.0;
+include "qelib1.inc";
+qreg q[3];
+creg a[2];
+cz q[0],q[2];
+gpi2(0.3) q[1];
+cz q[1],q[2];
+measure q[0] -> a[0];
+measure q[2] -> a[1];"""
+
+## or read in an assembly-file
+
+# set load_circuit to 'True' to overwrite the circuit above
+load_circuit = False
+if load_circuit:
+    try:
+        with open("./circuits1.qasm" "r") as qasm_file:
+            circuit = qasm_file.read()
+    except FileNotFoundError:
+        print("File not found!")
+    except Exception as e:
+        print(f"An error occurred: {e}")
+
+measurement = execute_qasm(circuit, platform="dummy", nshots=4000)
+
+freq = measurement.frequencies()
+p0 = freq["0"] / 4000 if "0" in freq else 0
+p1 = freq["1"] / 4000 if "1" in freq else 0
+hardware = [p0, p1]
+
+# plot results
+exp_angles = np.arange(0, 2 * np.pi, np.pi / 16)
+plt.plot(exp_angles, hardware, label="qibolab hardware")
+
+plt.legend()
+plt.ylabel("P(1)")
+plt.xlabel("Rotation [rad]")
+plt.show()