[Milestone] External Contributor Friendly

[mfw78]

Milestone: https://github.com/cowprotocol/pm/milestone/1
Priority Tracks: Production Readiness, Growth

Summary

Enable external developers to easily build with CoW Protocol, and contribute to cowprotocol repositories.

This milestone will deliver the following:

1. Documentation

In addition to generally updating the documentation so that information retained is relevant, the documentation is to be updated to follow an "actor" based methodology, allowing developers / users to easily lookup documentation based on their desired act within CoW Protocol.

In order to assess the usability of the new documentation format, feedback mechanisms will be required.

2. Contained, forkable repositories

Provide contained, narrow, opinionated repositories that developers can easily clone (essentially providing a "github recipes"). These are to be tightly coupled, and thus complimentary to documentation.

Justification

Due to rapid iteration, examples and documentation often dates rapidly for CoW Protocol. This barrier for entry needs to be lowered significantly in order to encourage external contributors / developers.

RAID (Risks, Assumptions, Issues and Dependencies)

Dependencies: @cowprotocol/frontend for docusaurus theming.