Improve member access in semantic check

[Brofian]

1. If the semantic check fails to find a matching member in one class, it should search for that member in the parent class and return that instead
2. Members should be checked for access modifiers and throw an error, if the referenced member is not allowed to be accessed from the current scope

[Brofian]

Part 1 (member inheriting) will be done by PR #37

Reminder for part 2: We would need a call origin to be passed to the member check, so we can compare the origin class or package name according to the access modifier