feat(compose): Docker Compose plugin

[edvald]

Still a bunch to be done, and currently branched off the plugin-sdk-pt2.
Just putting here for safe keeping and early review if anyone is particularly interested .)

[thsig]

This is now ready for review.

From the guide:

This plugin allows you to integrate Docker Compose projects into your Garden project.

It works by parsing the Docker Compose projects, and creating Build and Deploy actions for each service in the project.

You can then easily add Run and Test actions to complement your Compose project.

This can be very useful e.g. for running tests against a Docker Compose stack in CI (and locally), and to wrap various scripts you use during development (e.g. a Run for seeding a database with test data, or a Run for generating a database migration inside a container that you're developing).

The provided action types are (links point to the corresponding reference docs):

• docker-compose-service (Build and Deploy): These wrap the build and deploy (service) steps defined in a Compose project.
  • The docker-compose-service Build action calls docker compose build <service-name> under the hood.
  • The docker-compose-service Deploy action calls docker compose up <service-name> under the hood.
• docker-compose-exec (Run and Test): These use docker compose exec to execute the specified command in an already running Docker Compose service.
• docker-compose-run (Run and Test): These use docker compose run to run the specified command in a new container based on the Docker Compose service.
• docker-run (Run and Test): Like docker-compose-run, but these are independent of the Docker Compose project, and simply reference a Docker image tag to run (uses docker run under the hood).

Here's a screenshot and a screencap of the plugin in action:

docker-compose-readme-recording.mov

[thsig]

How do we feel about this one, @edvald?

I think it should be good for merging (would be good to get it on main and do any further work on this from there to close this long-lived PR).