[Proposal] Documentation coverage and static documentation site

[dest1n1s]

It is much easier for people (who may be new to mechanistic interpretability) to get started with detailed tutorial and documentation. Currently this project lacks documentation and comments in many modules. We should raise the documentation coverage, to ensure detailed explanation of every part of our library.

Furthermore, we should consider building a static documentation site with tools like MkDocs. This helps people get an overview of the usage of the library without actually downloading it.