feat: Remove device information in image class (#735)

Closes #524 

### Summary of Changes

feat: removed device from `Image`
feat: all internal pytorch objects now use the specified device
feat: auto selection of default device (defaults to `cuda` if `cuda` is
available)
test: added tests with `cuda` device

---------

Co-authored-by: megalinter-bot <129584137+megalinter-bot@users.noreply.github.com>

src/safeds/_config/__init__.py

@@ -5,15 +5,17 @@
 import apipkg
 
 if TYPE_CHECKING:
-    from ._device import _get_device
+    from ._device import _get_device, _init_default_device
 
 apipkg.initpkg(
     __name__,
     {
         "_get_device": "._device:_get_device",
+        "_init_default_device": "._device:_init_default_device",
     },
 )
 
 __all__ = [
     "_get_device",
+    "_init_default_device",
 ]

src/safeds/_config/_device.py

@@ -6,7 +6,29 @@
     from torch.types import Device
 
 
+_default_device: Device | None = None
+
+
 def _get_device() -> Device:
     import torch
 
-    return torch.device("cuda") if torch.cuda.is_available() else torch.device("cpu")
+    return torch.get_default_device()
+
+
+def _init_default_device() -> None:
+    import torch
+
+    global _default_device
+
+    if _default_device is None:
+        _default_device = torch.device("cuda") if torch.cuda.is_available() else torch.device("cpu")
+
+    torch.set_default_device(_default_device)
+
+
+def _set_default_device(device: Device) -> None:
+    # This changes all future tensors, but not any tensor that already exists
+    global _default_device
+
+    _default_device = device
+    _init_default_device()