enhance: bind-mount job paths through the docker proxy (#1226)

Containers a job starts through its Docker socket, for example `docker run -v "$PWD:/src"`, `./data:/data` in docker compose, or actions like dockerfile-roast, can now bind-mount the workspace and other paths the job sees, as on a host, without `bind_workdir`.

The per-job Docker proxy rewrites container and volume create requests. A bind source, or the device of a `local` volume with `o: bind`, that lies under one of the job container's mounts is pointed at that mount's path on the daemon, read from inspecting the job container. Paths that already name a daemon path, like `GITEA_DOCKER_WORKSPACE`, and paths outside the job's mounts pass through unchanged.

The proxy now also starts when the runner runs in a container given the host's Docker socket, by placing its socket in the runner's working directory, and in rootless dind, by granting the daemon socket's group through an ACL.

Fixes https://gitea.com/gitea/runner/issues/1219
Fixes https://gitea.com/gitea/runner/issues/1193

Reviewed-on: https://gitea.com/gitea/runner/pulls/1226
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <2021+silverwind@noreply.gitea.com>

act/container/docker_proxy_windows.go

@@ -10,6 +10,6 @@ import (
 	"os"
 )
 
-func copyDockerSocketPermissions(_ string, _ os.FileInfo) error {
+func copyDockerSocketPermissions(_, _ string, _ os.FileInfo) error {
 	return errors.New("docker socket ownership cannot be preserved on Windows")
 }