[REQ] Refactoring break allModels variable into seperate method

Created by: AIexG

Is your feature request related to a problem? Please describe.

Specific code generators might need to override updateAllModels().

Describe the solution you'd like

Breaking updateAllModels() variable allModels indexing apart into getAllModels() to prevent code duplication.

Describe alternatives you've considered

Additional context

I'm currently trying to improve the cpp-restbed codegen and the changes require an override on updateAllModels() and its variable allModels.

Already creating a PR for this.