Clean up the ontology package names and documentations for ontology convention

[hunterhector]

Is your feature request related to a problem? Please describe. Ontology class name could be a problem when multiple ones are used, since Python may not be able to pick the right package if they share the same suffix. We should provide guidelines of how to avoid such problems, and clean up the internal ontologies to reflect that.

Describe the solution you'd like

1. Create clear documentation on the convention of ontology, probably fixing the tutorial.
2. Modify the internal example ontologies, such as the clinical and race ontology, moving them to ftx, and follow other conventions.

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.