Makes the truncation length an attribute of the model

[Dntfreitas]

Changes:

1. Refactor: Renamed the wrapper to a more general name for improved clarity and coherence.
2. Enhancement: Introduced a dynamic max_tokens parameter to make truncation length more adaptable, taking into account model-specific requirements.
3. Configuration: Added 'key.txt' to the list of ignored files for a cleaner and secure repository structure.
4. Optimization: Removed the redundant model inclusion from main_from_text.py, since it was already defined in main.py.