Clean up documentation

[JanCBrammer]

Archive "dead" and legacy docs

Distinguish "living" (i.e., those docs that will be edited / extended during development) from "archive-able" docs, and move the "archive-able" docs out of the way (e.g., sub-directory, external archive) to de-clutter the repo.

File formats

Where possible, unify documentation file format. Preferably Markdown, or another editable plain-text format. Currently, a majority of the docs are in non-plain-text formats (.docx, pdf). The latter formats cannot be edited (conveniently), and they won't be displayed on GitHub. That is, those formats add unnecessary friction to reading and editing docs.

[cm-beilstein]

As discussed yesterday (03-12-2025) the consensus is to only keep the Markdown (*.md) files in the InChI-repo (path: INCHI-1-DOC):

• Create a list of essential files to be kept
• Convert files that don't have a Markdown version to Markdown
• Make sure that Markdown files contain everything that's in the other file formats (i.e., content of .md files is superset of the content that's in all other file formats)
• Remove all other file formats such as pdf, docx, ... .
• Set up a pipeline that can automatically generate common file formats (pdf/docx) and place them so they can be easily downloaded.

[nbehrnd]

• Regarding the conversion to pdf, docx, etc: pandoc can be used as an extra docker image, which can be tool within a GitHub workflow. For a starter, see here. Caveat: the present files about the documentation include .wmf / windows metafiles, a format specific to the Windows operating system and not supported by (pdf)LaTeX (.pdf, .png, .jp[e]g are). With the additional eisvogel template, one doesn't need to set up style file oneself (at moment of writing, an example is topic of pending PR42.
• To check the .md the syntax for correctness and consistency, one can consider a linter like markdownlint. For recurrent use, the adjustable rules can saved in a style file.