This is a great idea. The fact is that our architecture is currently changing a lot. At the moment, the "api" is quite stable but expect it to change.
The new architecture is the one used in the new beta program (www.codingame.com/contribute). At the moment, it is used only for courses created with this tool but we will probably move the whole system to this new architecture in the future.
The reason is that it is more flexible (the community will be able to create new languages, update them, add frameworks and so on), more powerful and standardised (Git and Docker, yes )
As we have a risk to change the "API" in the future, we can't take the time to code a probably already obsolete API.
However, if you want to suggest an API structure for your needs, for sure we will look at it and try to do our best to integrate it during the migration.