chore(examples): improved model initialization consistancy

[samyosm]

I have made sure to maintain consistency across all examples by aligning them with the documentation, which uses an initialModel method for model initialization.

[muesli]

While I prefer the naming consistency (newModel -> initialModel), we should probably simplify the code as much as possible and get rid of the method in some examples. We're also planning to streamline the bubbles a bit and make them proper tea.Models.