Combine apidoc and autosummary

[jxrossel]

problem

The autosummary extension (https://www.sphinx-doc.org/en/master/usage/extensions/autosummary.html) provides nice summary tables, but no documentation content by default (the templates must be hacked for that: #7912). The apidoc extension (https://www.sphinx-doc.org/en/master/usage/extensions/apidoc.html) provides recursive api file generation, but no summary tables.

solution
Would it be possible to extend the apidoc extension to optionally include summary tables in the generated files? That way, we could have a single full-features approach to automatically document api's with minimal configuration

alternatives
Custom templates for the autosummary extensions, with their potential failings (see #7912)