feat: primitive params

[BeautyyuYanli]

Updatet execute_py

• Return result as python object List[Dict[str, Any]]
• Raise exceptions

[wey-gu]

• maybe it can reuse resultSet.as_primitive()?
• return raw resultSet can be optional(default false)?

[BeautyyuYanli]

return raw resultSet can be optional(default false)?

Typing would be dirty because Python<=3.7 doesn't support things to do override. So I just return the ResultSet.

[wey-gu]

docs: https://github.com/vesoft-inc/nebula-python/pull/352