Removing keras sources from dev branch

llvm/projects/keras/README.md

llvm/projects/keras/frontend/__init__.py

llvm/projects/keras/frontend/approxhpvm_translator.py

llvm/projects/keras/frontend/hpvm_dfg_translator.py

llvm/projects/keras/frontend/promise_translator.py

llvm/projects/keras/frontend/quantize_utils.py

llvm/projects/keras/frontend/setup.py

llvm/projects/keras/frontend/utils.py

llvm/projects/keras/frontend/weight_utils.py

llvm/projects/keras/keras_environment.yml

llvm/projects/keras/setup.py

llvm/projects/keras/src/alexnet.py

llvm/projects/keras/src/alexnet2.py

llvm/projects/keras/src/lenet.py

llvm/projects/keras/src/mobilenet_cifar10.py

llvm/projects/keras/src/mobilenet_shallow.py

llvm/projects/keras/src/mobilenetv2_cifar10.py

llvm/projects/keras/src/resnet.py

llvm/projects/keras/src/vgg16_cifar10.py

llvm/projects/keras/src/vgg16_cifar100.py