Builtin Nematization

[ken-morel]

Is your feature request related to a problem? Please describe.
Requires nltk for Nematization

Describe the solution you'd like
Employ builtin nematization in djamago by using builtin variables instead of nltk

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.