Add support for `depends_on` argument

[andreybleme]

A docker-compose.yml file can contain many "depends_on" arguments, making certain services to start before others.

Supporting this would be nice, since this is a heavily used arg.

https://docs.docker.com/reference/compose-file/services/#depends_on

[noghartt]

I think that this would be a good addition, but it would be something we should do in our end, considering that container doesn't support it natively.

Some way we could solve it is creating a kind of graph of dependencies between the containers.

[andreybleme]

Yea, just like docker doesn't support dependencies natively for docker-compose, I think container will never support it for container-compose lol

We could borrow this "dependencies label" idea from docker-compose.
https://github.com/docker/compose/blob/main/pkg/compose/create.go#L491
https://github.com/docker/compose/blob/main/pkg/compose/compose.go#L195
https://github.com/docker/compose/blob/main/pkg/compose/convergence.go#L883

In summary:
The main function prepares a "dependencies" label, containing a set of dependencies each service contains.
The enforcement of the dependency is done later, through a convergence logic, where they sort services to start based on their dependencies.