Replace factory aliases with thin subclasses

Simple aliases like `BayBEKernelFactory = SmoothedEDBOKernelFactory`
cause the serialized type name to be that of the underlying class,
which means the identity is lost on deserialization. Using thin
subclasses ensures each factory has its own stable `__name__`.

Author: AdrianSosic

baybe/surrogates/gaussian_process/presets/baybe.py

@@ -29,17 +29,17 @@
     from torch import Tensor
 
 
-_BayBENumericalKernelFactory = _SmoothedEDBONumericalKernelFactory
-"""The factory providing the default numerical kernel for Gaussian process surrogates."""  # noqa: E501
+class _BayBENumericalKernelFactory(_SmoothedEDBONumericalKernelFactory):
+    """The default numerical kernel factory for GP surrogates."""
 
 
-BayBEKernelFactory = SmoothedEDBOKernelFactory
-"""The default kernel factory for Gaussian process surrogates."""
+class BayBEKernelFactory(SmoothedEDBOKernelFactory):
+    """The default kernel factory for GP surrogates."""
 
 
 @define
 class _BayBETaskKernelFactory(_PureKernelFactory):
-    """The factory providing the default task kernel for Gaussian process surrogates."""
+    """The default task kernel factory for GP surrogates."""
 
     _uses_parameter_names: ClassVar[bool] = True
     # See base class.
@@ -64,11 +64,13 @@ def _make(
         )
 
 
-BayBEMeanFactory = LazyConstantMeanFactory
-"""The factory providing the default mean function for Gaussian process surrogates."""
+class BayBEMeanFactory(LazyConstantMeanFactory):
+    """The default mean factory for GP surrogates."""
+
+
+class BayBELikelihoodFactory(SmoothedEDBOLikelihoodFactory):
+    """The default likelihood factory for GP surrogates."""
 
-BayBELikelihoodFactory = SmoothedEDBOLikelihoodFactory
-"""The factory providing the default likelihood for Gaussian process surrogates."""
 
 # Aliases for generic preset imports
 PresetKernelFactory = BayBEKernelFactory

baybe/surrogates/gaussian_process/presets/edbo.py

@@ -113,8 +113,8 @@ def _make(
         )
 
 
-EDBOMeanFactory = LazyConstantMeanFactory
-"""A factory providing mean functions for the EDBO preset."""
+class EDBOMeanFactory(LazyConstantMeanFactory):
+    """A factory providing mean functions for the EDBO preset."""
 
 
 @define

baybe/surrogates/gaussian_process/presets/edbo_smoothed.py

@@ -83,8 +83,9 @@ def _make(
 and interpolates the prior moments linearly in between.
 """  # noqa: E501
 
-SmoothedEDBOMeanFactory = LazyConstantMeanFactory
-"""A factory providing mean functions for the smoothed EDBO preset."""
+
+class SmoothedEDBOMeanFactory(LazyConstantMeanFactory):
+    """A factory providing mean functions for the smoothed EDBO preset."""
 
 
 @define