feat: root event diff script (#1737)

small python script to check in which event a diff in a root file occurs 

can be invoked like the following

```
python CI/root_event_diff_np.py tracksummary_gsf_a.root:tracksummary tracksummary_gsf_b.root:tracksummary
```

CI/root_event_diff_np.py

@@ -0,0 +1,69 @@
+import sys
+import argparse
+import numpy as np
+import uproot
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("a")
+parser.add_argument("b")
+parser.add_argument("--event-nr", default="event_nr")
+parser.add_argument("--fail-fast", action="store_true")
+args = parser.parse_args()
+
+a_data = uproot.open(args.a)
+b_data = uproot.open(args.b)
+event_nr = args.event_nr
+fail_fast = args.fail_fast
+
+a_sort_index = np.argsort(a_data[event_nr].array(library="np"), kind="stable")
+b_sort_index = np.argsort(b_data[event_nr].array(library="np"), kind="stable")
+
+np.set_printoptions(linewidth=np.inf)
+
+
+def cmp(a, b):
+    if np.isscalar(a):
+        if a != b:
+            return False
+    elif type(a) == np.ndarray:
+        if not np.array_equal(a, b, equal_nan=True):
+            return False
+    else:
+        for aa, bb in zip(a, b):
+            if not cmp(aa, bb):
+                return False
+    return True
+
+
+failed_events = set()
+failed_keys = set()
+for key in a_data.keys():
+    if key == event_nr:
+        continue
+
+    a_vals = a_data[key].array(library="np")
+    a_vals = a_vals[a_sort_index]
+
+    b_vals = b_data[key].array(library="np")
+    b_vals = b_vals[b_sort_index]
+
+    for event, (a, b) in enumerate(zip(a_vals, b_vals)):
+        if not cmp(a, b):
+            print(f"event {event} failed for {key}")
+            print(f"a {a}")
+            print(f"b {b}")
+            print()
+
+            if fail_fast:
+                sys.exit(1)
+            failed_events.add(event)
+            failed_keys.add(key)
+
+if failed_events or failed_keys:
+    print("summary")
+    print("failed events: " + " ".join(map(str, sorted(failed_events))))
+    print("failed keys: " + " ".join(failed_keys))
+    sys.exit(1)
+
+sys.exit(0)