Option to only generate autosummary stubs for parent class

[ma-sadeghi]

Is your feature request related to a problem? Please describe.
In projects with lots of nested class hierarchy, autosummary generates tons of "individual" "identical" stubs for inherited members, for instance: if we have A > B > C > D, and A has 10 methods that are inherited by the other 3 classes, autosummary generates 40 stubs, which adds to the build time.

Describe the solution you'd like
Option to only generate stubs for the parent class, and link the docs page for the inherited members to that stub.