Refactor XAI functionality

[stavrostheocharis]

Description
The XAI pipeline runs produces a custom dictionary as an output. This output is not easy to be visualized in the streamlit.
In addition, this XAI requires a connection with an S3 in order to get the data (model, etc.) from there.

Solution

• Define and implement how the results should be visualized (the easiest way is to visualize the plot itself directly as produced by lime, the other case is to create a custom plot)

[momegas]

Where can the user upload a model? Does this exist in the UI now?

[NickNtamp]

This is a bit blur for me @stavrostheocharis . Can you please elaborate? No need for S3 connection is required for level0 of confidence.

[momegas]

We removed the S3, because it was confusing, so it is just the fix. I propose an endpoint that produces the image and a separate one that returns the normal json response. I propose we return the lime Dict here as is (typed of course)