Feature/azaytsev/g api docs (openvinotoolkit#3731)

* Initial commit

* Added content

* Added new content for g-api documentation. Removed obsolete links through all docs

* Fixed layout

* Fixed layout

* Added new topics

* Added new info

* added a note

* Removed redundant .svg

docs/get_started/get_started_dl_workbench.md

@@ -136,5 +136,4 @@ For detailed instructions to create a new project, visit the links below:
 * [Inference Engine Developer Guide](../IE_DG/Deep_Learning_Inference_Engine_DevGuide.md)
 * [Model Optimizer Developer Guide](../MO_DG/Deep_Learning_Model_Optimizer_DevGuide.md)
 * [Inference Engine Samples Overview](../IE_DG/Samples_Overview.md)
-* [Overview of OpenVINO™ Toolkit Pre-Trained Models](https://software.intel.com/en-us/openvino-toolkit/documentation/pretrained-models)
-* [OpenVINO™ Hello World Face Detection Exercise](https://github.com/intel-iot-devkit/inference-tutorials-generic)
+* [Overview of OpenVINO™ Toolkit Pre-Trained Models](https://software.intel.com/en-us/openvino-toolkit/documentation/pretrained-models)