🚀 Feature

Idea is to replace our manually created toctree for metrics, handlers, regression metrics etc.

How to do that :

• check .. autosummary:: tag in Sphinx
• add it and configure for each listed above .rst file : metrics.rst, handlers.rst etc

Example of usage:

• https://numpy.org/devdocs/reference/arrays.ndarray.html#id1
• https://github.com/numpy/numpy/blob/master/doc/source/reference/arrays.rst (edited)

This issue maybe or maybe not blocked by #1272

For Hacktoberfest contributors, feel free to ask questions for details if any and say that you would like to tackle the issue.
Please, take a look at CONTRIBUTING guide.