add a podman-compose command

**podman compose** is a thin wrapper around an external compose provider
such as docker-compose or podman-compose.  This means that `podman
compose` is executing another tool that implements the compose
functionality but sets up the environment in a way to let the compose
provider communicate transparently with the local Podman socket.  The
specified options as well the command and argument are passed directly
to the compose provider.

The default compose providers are `docker-compose` and `podman-compose`.
If installed, `docker-compose` takes precedence since it is the original
implementation of the Compose specification and is widely used on the
supported platforms (i.e., Linux, Mac OS, Windows).

If you want to change the default behavior or have a custom installation
path for your provider of choice, please change the `compose_provider`
field in `containers.conf(5)`.  You may also set the
`PODMAN_COMPOSE_PROVIDER` environment variable.

Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

vendor/github.com/containers/common/pkg/config/default.go

@@ -87,6 +87,16 @@ var (
 	// should be set during link-time, if different packagers put their
 	// helper binary in a different location.
 	additionalHelperBinariesDir string
+
+	defaultUnixComposeProviders = []string{
+		"docker-compose",
+		"$HOME/.docker/cli-plugins/docker-compose",
+		"/usr/local/lib/docker/cli-plugins/docker-compose",
+		"/usr/local/libexec/docker/cli-plugins/docker-compose",
+		"/usr/lib/docker/cli-plugins/docker-compose",
+		"/usr/libexec/docker/cli-plugins/docker-compose",
+		"podman-compose",
+	}
 )
 
 // nolint:unparam
@@ -260,6 +270,8 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 	c.EventsLogFileMaxSize = eventsLogMaxSize(DefaultEventsLogSizeMax)
 
 	c.CompatAPIEnforceDockerHub = true
+	c.ComposeProviders = getDefaultComposeProviders() // may vary across supported platforms
+	c.ComposeWarningLogs = true
 
 	if path, ok := os.LookupEnv("CONTAINERS_STORAGE_CONF"); ok {
 		if err := types.SetDefaultConfigFilePath(path); err != nil {
@@ -406,6 +418,7 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 		"runsc",
 		"youki",
 		"krun",
+		"ocijail",
 	}
 	c.RuntimeSupportsNoCgroups = []string{"crun", "krun"}
 	c.RuntimeSupportsKVM = []string{"kata", "kata-runtime", "kata-qemu", "kata-fc", "krun"}