Add a memory demanding feature in the TF based transformers

bob/bio/face/config/baseline/facenet_sanderberg.py

...o/face/config/baseline/inception_resnetv1_casiawebface.py

bob/bio/face/config/baseline/inception_resnetv1_msceleb.py

...o/face/config/baseline/inception_resnetv2_casiawebface.py

bob/bio/face/config/baseline/inception_resnetv2_msceleb.py

bob/bio/face/config/baseline/tf2_inception_resnet.py

bob/bio/face/embeddings/tf2_inception_resnet.py

bob/bio/face/test/test_embeddings.py