[ISSUE][DOCS] Missing API reference

[sptramer]

Describe the issue

Some API reference appears to be missing due to relying on a private base class which isn't exposed in the docs generation (see https://github.com/o3de/o3de.org/pull/2009). Doxygen does not have an easy mechanism for detecting docs dependencies like this; You can either publish everything from private or nothing from private (same with protected). This isn't quite a misfeature of Doxygen but requires further investigation.

Impacted page(s)

Any page linking to class_az_framework_1_1_spawnable_1_1_entity_alias_visitor_base.html in the API reference and the documentation for this class itself.

Expected experience

API ref is comprehensive for:

• Public classes
• protected and friend classes which are used for base classes or virtual function dispatch
• private classes which are used as base classes for public or protected classes

[chanmosq]

We may not be able to resolve this issue with our current API reference generator because Doxygen doesn't seem to support generating for protected and private classes. However, this is a very important issue or need to note when we look into using another API reference generator.

For now, we'll leave this issue open. It needs more research.