Introduce OpSignature to IR (#1838)

Introduce OpSignature accessible from the `.op_signature` property of
all OpLike objects (traced function, onnx function and op). The
OpSignature class leverages the IR to represent the signature of an
operator, preserving ordering of all inputs and provides easy to work
with type representations.

The PR also deprecates the ParamSchema class and properties.

Fixes #1697

The next PR will replace param_schemas usage.

onnxscript/_internal/deprecation.py

@@ -12,6 +12,12 @@
 T = TypeVar("T")
 
 
+@functools.lru_cache(maxsize=1024)
+def _warn_once(message: str):
+    """Issue a FutureWarning only once per message."""
+    warnings.warn(message, category=FutureWarning, stacklevel=3)
+
+
 def deprecated(since: str, removed_in: str, instructions: str) -> Callable[[T], T]:
     """Marks functions as deprecated.
 
@@ -30,12 +36,10 @@ def deprecated(since: str, removed_in: str, instructions: str) -> Callable[[T],
     def decorator(function):
         @functools.wraps(function)
         def wrapper(*args, **kwargs):
-            warnings.warn(
+            _warn_once(
                 f"'{function.__module__}.{function.__qualname__}' "
                 f"is deprecated in version {since} and will be "
                 f"removed in {removed_in}. Please {instructions}.",
-                category=FutureWarning,
-                stacklevel=2,
             )
             return function(*args, **kwargs)