Previously in #18635 we delayed the containers API `Init` to avoid producing
errors due to Docker and `@devcontainers/cli` not yet being installed by startup
scripts. This had an adverse effect on the UX via UI responsiveness as the
detection of devcontainers was greatly delayed.
This change splits `Init` into `Init` and `Start` so that we can immediately
after `Init` start serving known devcontainers (defined in Terraform), improving
the UX.
Related #18635
Related #18640
0f3a1e9849