Adapt execute_entrypoint to execute the new contract classes

[marco-paulucci]

Depends on #313

We need to update our execute_entrypoint module to take into account the new contract. classes from cairo 1. In cairo-lang 0.11 this is implemented in the execute_entrypoint.py module using an IF statement and switching to the relevant implementation based on the type of the contractClass being executed. We should do something similar and implement the execute_version0 and the new execute methods.

[ElFantasma]

I'm closing this issue as it was partitioned in two sub issues:

• Implement new compiled classes execution flow in execute_entrypoint module
• Investigate and update the old contract classes execution flow