rename the execute function

[Fabien-GELUS]

In function.py we have 2 different execute functions, and it's really difficult when calling for instance function.execute([to know which one is used, we have to track the function object type.
I propose to rename one of them, like execute_function for the one in wrapper or execute_cli for the one running the cli

[ThibaultFy]

I agree that it is confusing. I propose to keep execute for the cli as it is the function exposed to the user, in order to keep a name as simple as possible, and to rename to execute_function for the wrapper.