[Story] Baseline Matrix backend documentation for MPS

[Gnuxie]

Description

As a client developer, I want to use MPS to read and write policies but there isn't a library that supports my Matrix backend. Therefore I need to develop a new backend similar to the matrix-protection-suite-for-matrix-bot-sdk library. I need to have documentation available to me that will tell me what interfaces need to be implemented in my client in order to use MPS.

Acceptance Criteria

• A complete reference of all the interfaces that a backend needs to implement is available to me.
• Explanations exist for the main sources of Matrix IO, the room state manager, policy room manager and room membership manager.
• A how to guide exists for implementing a backend that can receive all the policy information that Draupnir does.
• A tutorial exists for creating a simple and bare bones policy room editor that only needs to implement parts of the PolicyRoomManager and PolicyRoomEditor interfaces.

Issues

Dependencies

• [Story] Baseline documentation for MPS #12

Total Pain