Reorganize the API Reference Section of the Documentation
The API Reference section of the documentation has been reorganized. The landing page of the section now exclude the full table of contents in favor of tabular view of the most relevant top-level sub-packages. Furthermore, the in-code documentation, especially the package- and module-level docstrings, has been extensively updated for the relevant function.
This commit does not introduce any changes to the codebase beyond the relevant docstrings and therefore there should not be a functional change. This MR should resolve Issue #180 (closed) and part of the documentation summer sprint (Issue #178).