text: Title: Add RNN/LSTM support
  Body: ### Description
  
  We want to add support for RNNs. I will let this issue open for people who want to contribute to this project. 
  My suggestion would be just to write RNN (or any other RNN-like model) in the algorithm field in order to use an RNN model. Here is an example to illustrate what I mean:
  
  ```
  model:
       type: classification
       algorithm: RNN
      .
      . 
  
  ```
  
  **If you are willing to work on this, please just start and don't wait for my approval.**
  Anyone is free to join the [discussion](https://github.com/nidhaloff/igel/discussions/80) to share ideas. 
  