Solve which agents we should offer to the user when creating workspace

Problem

User selecting project-agent pair

The user wants to create a workspace for a project. Rails needs to know which agents can be used by the user and the project.

Admin adding an agent to the GitLab instance/group/project

Admin/maintainer wants an agent to be available for creating new workspaces. Where should they configure this?

Solution

Described in https://gitlab.com/gitlab-org/remote-development/gitlab-remote-development-docs/-/blob/3ff9b9a41525a06961992bfa3897ae8d22c11d0f/doc/mapping-projects-to-agents.md