Create basic structure of the docs for version 2.0

🧩 User Story

As a users as well as developers I want to have an extensive documentation, in order to quickly get as much information as possible about the software myself.

🎯 Goal & Context

The new documentation should be derived from what's already there with the docs of CIVITAS/CORE version 1, such that existing users will quickly find their way around. The goal ist to offer everyone a very extensive documentation providing all potentially useful information for end users, service providers and developers.

🛑 Boundaries & Implementation Notes

Docusaurus shall be used. Consider the multi-instance feature of docusaurus, if you find this useful.

✅ Acceptance Criteria

This issue is considered done when:

• there is a concept of how to implement the requirements
• the concept has been approved by the product owner before being implemented
• the docs follow a similar overall structure than the one for Version 1. The developments in the docs of version 1.3 is taken into account, in particular the new "dev" section
• the docs are available unter the same URL as for version 1, and offer versioned docs for version 2 as well.
• a version 2.0 is created and marked as draft
• the docs contain all relevant areas of what has been discussed recently with the architects, e.g. overall architecture, architecture decision records, risks, ..., as well as a glossar and other relevant parts. They do not have to be complete regarding their content.
• if useful, the README of the docs repo is extended with relevant guides about how to use the docs for version 2