Refactor DTDeepJSCC model to remove MNIST architecture support

- Removed MNIST-specific code from Xie2023DTDeepJSCCEncoder and Xie2023DTDeepJSCCDecoder classes, including initialization parameters and encoder/decoder methods.
- Updated documentation to reflect the removal of MNIST architecture options.
- Simplified encoder and decoder tests by eliminating MNIST-related fixtures and test cases.
- Enhanced the forward methods to ensure compatibility with only CIFAR-10 and custom architectures.
- Improved parallel processing in CapacityAnalyzer by defining a class method for mutual information calculation.
- Added handling for dynamic batch sizes and input sizes in the decoder's forward method.

Author: selimfirat

docs/Makefile

@@ -16,7 +16,7 @@ help:
 
 clean:
 	rm -rf $(BUILDDIR)
-	rm -rf auto_examples
+#	rm -rf auto_examples
 	rm -rf generated
 	rm -rf gen_modules