Python: Add support for dynamic imports

```python
import foo_slint
```

will now also look for `foo.slint`

api/python/tests/test_import.py

@@ -0,0 +1,27 @@
+# Copyright © SixtyFPS GmbH <info@slint.dev>
+# SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.1 OR LicenseRef-Slint-commercial
+
+import pytest
+from slint import slint as native
+import sys
+import os
+
+
+def test_magic_import():
+    import test_load_file_slint as compiledmodule
+    instance = compiledmodule.App()
+    del instance
+
+
+def test_magic_import_path():
+    oldsyspath = sys.path
+    with pytest.raises(ModuleNotFoundError, match="No module named 'printerdemo_slint'"):
+        import printerdemo_slint
+    try:
+        sys.path.append(os.path.join(os.path.dirname(__file__),
+                        "..", "..", "..", "examples", "printerdemo", "ui"))
+        import printerdemo_slint
+        instance = printerdemo_slint.MainWindow()
+        del instance
+    finally:
+        sys.path = oldsyspath