Support parameterized QASM3 export

Author: spital

releasenotes/notes/qasm3-parameterized-export-146-6f6f1d31c9e74d2b.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    `QuantumCircuit::to_qasm3()` now uses a dedicated OpenQASM 3 exporter and
+    declares symbolic circuit parameters as OpenQASM 3 `input float[64]`
+    values before emitting parameterized gate operations. Generated input and
+    register names are adjusted when needed to avoid OpenQASM 3 global symbol
+    conflicts, including conflicts with custom gate definitions emitted by the
+    exporter. The exporter also emits valid OpenQASM 3 for controlled-U1,
+    controlled-U3, and global phase operations.