Add minimal examples to Prophet model methods

[iKintosh]

🚀 Feature Request

Add Example section to Prophet model.
It should be in added to class description and show how to use CatBoost model.
Expected result should be TSDataset (not its values)

Motivation

Make documentation as much helpful as possible

Proposal

1. Create Example section in ProphetModel.
2. Generate dataframe
3. Fit model
4. Create future dataset
5. Forecast
6. Check if result is TSDataset or that all future dates are fulled (not NaN)

Test cases

This should be tested by doc test

Alternatives

No response

Additional context

No response

Checklist

• Added feature request
• Added motivation
• Added proposal