dcsg: add new recipe

It could be used to deploy a docker compose file to a rootfs, meanwhile
create and enable a systemd service to start the containers in it.

Two parameters are added to the original dcsg:
--root-dir: install the docker-compose and systemd service to a
            specific root directory.
--compose-dir: the users could install the docker compose file to this
            directory, it defaults to /opt/containers.

a native dcsg is also supported, to have a try, please follow:
```
$ bitbake dcsg-native
$ ./tmp-glibc/sysroots-components/x86_64/dcsg-native/usr/bin/dcsg --root-dir /tmp/dcsg install ./my-compose/docker-compose.yml
$ tree /tmp/dcsg
/tmp/dcsg/
├── etc
│   └── systemd
│       └── system
│           ├── multi-user.target.wants
│           │   └── mycompose.service -> /etc/systemd/system/mycompose.service
│           └── mycompose.service
└── opt
    └── containers
        └── docker-compose.yml
```

Signed-off-by: Ming Liu <liu.ming50@gmail.com>