Move contents `client_models` to `net.models`, deprecate `client_models`.

[cptartur]

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

Refactor starknet.py so all our client related models are in net.models module.

Describe the solution you'd like

Move contents of client_models.py to separate files in net.models and deprecate it.

Describe alternatives you've considered

none

Additional context

n/a