feat: wait for healthy services and fill the job context (#1107)

Service containers were started and then left alone, so a job's first step could run while a database was still starting up. The runner now waits for every service whose image or `options` declare a healthcheck, as GitHub does. An unhealthy service fails the job with its container log, one that never becomes healthy fails it after `container.service_ready_timeout` (default `5m`, negative disables the wait), and one that exits without a healthcheck only gets its log and a warning.

The started containers also fill the `job` context, whose fields existed but were never populated: `job.container.{id,network}` and `job.services.<id>.{id,network,ports}`. `ports` is keyed by the plain container port, so `job.services.postgres.ports['5432']` resolves to the host port Docker picked.

---------

Co-authored-by: silverwind <me@silverwind.io>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1107
Reviewed-by: silverwind <2021+silverwind@noreply.gitea.com>
Co-authored-by: bircni <bircni@icloud.com>

go.mod

@@ -37,6 +37,7 @@ require (
 	go.etcd.io/bbolt v1.5.0
 	go.yaml.in/yaml/v4 v4.0.0-rc.3
 	golang.org/x/net v0.57.0
+	golang.org/x/sync v0.22.0
 	golang.org/x/sys v0.47.0
 	golang.org/x/term v0.45.0
 	golang.org/x/text v0.40.0
@@ -104,7 +105,6 @@ require (
 	go.opentelemetry.io/otel/trace v1.44.0 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.54.0 // indirect
-	golang.org/x/sync v0.22.0 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )