[doc] Add dependency graphs to documentation

Is your feature request related to a problem? Please describe.

I'm always frustrated when I can't see updated dependency graphs in the documentation, showing the actual dependencies between modules as parsed by Doxygen. (yeah right)

Context

Provide an updated view on dependencies not requiring delving into CMakeLists.txts or using old images available online.

Expected behavior

The documentation available at https://pointcloudlibrary.github.io/documentation/modules.html could include a generated graph from the code.

Current Behavior

There is no graph available in the modules inside that webpage.

Describe the solution you'd like

There is a graph available for each module inside that webpage. Generated via Doxygen to make it "easy" as it should be available thanks to the GROUP_GRAPHS configuration option which is currently enabled as well in our doxyfile.

Describe alternatives you've considered

It's a nice-to-have, not anything mandatory, so no other alternatives yet.

Additional context

This issue template is really in depth.

Start with the repository's doxyfile and documentation generation setup, then inspect the modules documentation at pointcloudlibrary.github.io/documentation/modules.html. Check how GROUP_GRAPHS is configured and how module pages are generated. Done means the published documentation includes a generated dependency graph for each module.