Docs controller: generic markdown parser

Use this project to support a generic documentation engine with markdown files:

https://weblog.west-wind.com/posts/2018/Apr/18/Creating-a-generic-Markdown-Page-Handler-using-ASPNET-Core-Middleware

Markdown editor:

https://marketplace.visualstudio.com/items?itemName=SyncfusionInc.aspnet-mvc-wysiwyg-rich-text-editor

There's also this thing:
https://docsify.now.sh/

Start by reviewing the linked article on a generic Markdown page handler, then compare its approach with the project’s existing ASP.NET Core entry points. The issue mentions no files or tests; done would require a documented generic documentation engine that supports Markdown files, with the editor and docsify options resolved.

Written by the indexing model from the issue text.