Replace deprecated strtobool function (#3760)

The `distutils` module has been deprecated in Python 3.10 and removed in
Python 3.12, [see docs
distutils](https://docs.python.org/3/library/distutils.html).

The [migration
advice](https://peps.python.org/pep-0632/#migration-advice):
> For these functions, and any others not mentioned here, you will need
to reimplement the functionality yourself.
> `distutils.util.strtobool`

Copied the strtobool function from 3.11 and adjusted it to return
booleans, like our function did.

app/grandchallenge/core/utils/__init__.py

@@ -1,4 +1,3 @@
-from distutils.util import strtobool as strtobool_i
 from functools import wraps
 
 
@@ -16,6 +15,17 @@ def wrapper(*args, **kwargs):
     return wrapper
 
 
-def strtobool(val) -> bool:
-    """Return disutils.util.strtobool as a boolean."""
-    return bool(strtobool_i(val))
+def strtobool(val):
+    """Convert a string representation of truth to true or false.
+
+    True values are 'y', 'yes', 't', 'true', 'on', and '1'; false values
+    are 'n', 'no', 'f', 'false', 'off', and '0'.  Raises ValueError if
+    'val' is anything else.
+    """
+    val = val.lower()
+    if val in ("y", "yes", "t", "true", "on", "1"):
+        return True
+    elif val in ("n", "no", "f", "false", "off", "0"):
+        return False
+    else:
+        raise ValueError(f"invalid truth value {val}")

app/tests/core_tests/test_utils.py

@@ -0,0 +1,39 @@
+import pytest
+
+from grandchallenge.core.utils import strtobool
+
+
+@pytest.mark.parametrize(
+    "val, result",
+    [
+        ("y", True),
+        ("Y", True),
+        ("yes", True),
+        ("Yes", True),
+        ("true", True),
+        ("True", True),
+        ("t", True),
+        ("T", True),
+        ("on", True),
+        ("On", True),
+        ("1", True),
+        ("n", False),
+        ("N", False),
+        ("no", False),
+        ("No", False),
+        ("false", False),
+        ("False", False),
+        ("f", False),
+        ("F", False),
+        ("off", False),
+        ("Off", False),
+        ("0", False),
+    ],
+)
+def test_strtobool(val, result):
+    assert strtobool(val) is result
+
+
+def test_strtobool_exception():
+    with pytest.raises(ValueError):
+        strtobool("foobar")