Examples reorg (#11350)

* Base move

* Examples reorganization

* Update references

* Put back test data

* Move conftest

* More fixes

* Move test data to test fixtures

* Update path

* Apply suggestions from code review

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

* Address review comments and clean

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

examples/tensorflow/question-answering/README.md

@@ -0,0 +1,34 @@
+<!---
+Copyright 2020 The HuggingFace Team. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+## SQuAD with the Tensorflow Trainer
+
+```bash
+python run_tf_squad.py \
+    --model_name_or_path bert-base-uncased \
+    --output_dir model \
+    --max_seq_length 384 \
+    --num_train_epochs 2 \
+    --per_gpu_train_batch_size 8 \
+    --per_gpu_eval_batch_size 16 \
+    --do_train \
+    --logging_dir logs \    
+    --logging_steps 10 \
+    --learning_rate 3e-5 \
+    --doc_stride 128    
+```
+
+For the moment evaluation is not available in the Tensorflow Trainer only the training.