[Transform] add a give_unique_names transform

src/finn/transformation/general.py

+import copy
+
+
+def give_unique_names(model):
+    """Give unique names to each node in the graph using enumeration."""
+
+    new_model = copy.deepcopy(model)
+    node_count = 0
+    for n in new_model.graph.node:
+        n.name = "%s_%d" % (n.op_type, node_count)
+        node_count += 1
+    return new_model