feat: Allow set_status pass in skel and no key (#31)

Resolves:
>We could rather implement in the toolkit.set_status that you can pass a
skel, and it also reads the key from there, and you can omit the key
argument

viur-framework/viur-shop#29 (comment)

src/viur/toolkit/db.py

@@ -61,8 +61,8 @@ def txn(_key: db.Key, _name: str, _value: float | int, _start: float | int) -> f
 
 
 def set_status(
-    key: _KeyType,
-    values: dict | t.Callable[[skeleton.SkeletonInstance | db.Entity], None],
+    key: t.Optional[_KeyType] = None,
+    values: dict | t.Callable[[skeleton.SkeletonInstance | db.Entity], None] | None = None,
     precondition: t.Optional[dict | t.Callable[[skeleton.SkeletonInstance | db.Entity], None]] = None,
     create: dict[str, t.Any] | t.Callable[[skeleton.SkeletonInstance | db.Entity], None] | bool = False,
     skel: t.Optional[skeleton.SkeletonInstance] = None,
@@ -84,11 +84,15 @@ def set_status(
     If the function does not raise an Exception, all went well.
     It returns either the assigned skel, or the db.Entity on success.
     """
-
+    if key is None and skel is None:
+        raise ValueError("No Key is provided")
+    elif key is None and skel is not None:
+        key = skel["key"]
+    if values is None:
+        raise ValueError("No values provided")
     # Transactional function
     def transaction() -> skeleton.SkeletonInstance | db.Entity:
         exists = True
-
         # Use skel or db.Entity
         if skel:
             if not skel.fromDB(key):