(Docker 4/5) Release expired docker-autoscaler environments

What does this MR do?

Removes an expired or unusable environment's containers, networks and non-cache volumes, selected by both acquisition key and runner ID. Cleanup uses it when a resume finds the environment unusable. The TTL sweep in (Docker 5/5) Sweep expired suspended docker-aut... (!7667) calls ReleaseEnvironment for expired environments.

Why was this MR needed?

An environment that the orchestrator never releases holds its resources forever.

What's the best way to test this MR?

go test -race ./executors/docker/ ./executors/internal/autoscaler/ -run 'Release'

What are the relevant issue numbers?

Related to #39468.