Add retinanet convert doc

docs/MO_DG/prepare_model/convert_model/tf_specific/Convert_RetinaNet_From_Tensorflow.md

@@ -0,0 +1,15 @@
+# Converting RetinaNet Model from TensorFlow* to the Intermediate Representation {#openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_RetinaNet_From_Tensorflow}
+
+This tutorial explains how to convert RetinaNet model to the Intermediate Representation (IR).
+
+[Public RetinaNet model](https://github.com/fizyr/keras-retinanet) does not contain pretrained TensorFlow\* weights. 
+To convert this model to the TensorFlow\* format, you can use [Reproduce Keras* to TensorFlow* Conversion tutorial](https://docs.openvinotoolkit.org/latest/omz_models_model_retinanet_tf.html).
+
+After you convert the model to TensorFlow* format, run the Model Optimizer command below:
+```sh
+python mo.py --input "input_1[1 1333 1333 3]" --input_model retinanet_resnet50_coco_best_v2.1.0.pb --data_type FP32 --transformations_config ./extensions/front/tf/retinanet.json
+```
+
+Where `transformations_config` command-line parameter specifies the configuration json file containing model conversion hints for the Model Optimizer.
+The json file contains some parameters that need to be changed if you train the model yourself. It also contains information on how to match endpoints
+to replace the subgraph nodes. After the model is converted to IR, the output nodes will be replaced with DetectionOutput layer.

docs/doxygen/ie_docs.xml

@@ -34,6 +34,7 @@ limitations under the License.
                             <tab type="user" title="Converting DeepSpeech Model from TensorFlow" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_DeepSpeech_From_Tensorflow"/>
                             <tab type="user" title="Converting Language Model on One Billion Word Benchmark from TensorFlow" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_lm_1b_From_Tensorflow"/>
                             <tab type="user" title="Converting TensorFlow* Object Detection API Models" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_Object_Detection_API_Models"/>
+                            <tab type="user" title="Converting RetinaNet Model from TensorFlow" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_RetinaNet_From_Tensorflow"/>
                             <tab type="user" title="Converting TensorFlow*-Slim Image Classification Model Library Models" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_Slim_Library_Models"/>
                             <tab type="user" title="Converting CRNN Model from TensorFlow" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_CRNN_From_Tensorflow"/>
                             <tab type="user" title="Converting GNMT from TensorFlow" url="@ref openvino_docs_MO_DG_prepare_model_convert_model_tf_specific_Convert_GNMT_From_Tensorflow"/>