Toy Benchmark Base + rename to QuanDA🎉

[dilyabareeva]

• replacing DownstreamTasks with ToyBenchmarks
• Refactoring Subclass Detection accordingly
• a full usage script for CIFAR-10 and ResNet18
• metrics tested on CUDA - making fixes where appropriate
• renaming to Quanda
• miscellaneous improvements

[dilyabareeva]

Hi @gumityolcu, please review.