Feature: Export static documentation

[Salmondx]

It would be a great addition to this tool if it would be possible to generate static documentation that can be hosted on GitHub pages or other places, without the need for API consumers to install vscode extensions or cloning the repo.

For example, currently I used plugin for insomnia (https://github.com/insodoc/insomnia-documenter) to generate documentation but it requires to many manual steps.

Given that httpyac already ships with a great cli utility it would be possible to automate this process as well via GitHub actions.