[FEATURE] Add important tutorials to hub docs

## 🚨🚨 Feature Request

- [ ] Related to an existing [Issue](../issues)
- [ ] A new implementation (Improvement, Extension)

### Is your feature request related to a problem?

[Hub docs](https://docs.activeloop.ai/hub-tutorials) are missing the following tutorials in order of priority:

- Training an object detection model in Pytorch
- Training a segmentation model in Pytorch
- Training a classification model in TensorFlow
- Training an object detection model in TensorFlow
- Training a segmentation model in TensorFlow

### Tips for completing the task

- All of these tutorials can use the COCO dataset, because it contains all of the data types that are required above.
- When training the models, only the tensors that contain the relevant data should be loaded for training.
- The tutorials should be written in Gitbook and Colab
- The tutorials should use a similar style to the [existing classification tutorial](https://docs.activeloop.ai/hub-tutorials/training-an-image-classification-model-in-pytorch)
- The focus of the tutorials is the data and data pre-processing. The model and training process should be as simple as possible.

### If your feature will improve `HUB`

It will provide users helpful starter-code for training different types of models