Update daemon.sh and the documentation

[Turiok]

Add the possibility to use docker secret for swarm or compose.

It's related to the ticket #121

I validate the build on my computer. I didn't change the version of the application.

Here an example of docker-compose :

version: "3.4"
services:
  # JDownloader 2
  jdownloader:
    image: jaymoulin/jdownloader:2.0.3-amd64
    container_name: jdownloader2
    environment:
      - PUID=${PUID}
      - PGID=${PGID}
      - TZ=${TZ}
      - FILE_MYJD_USER=myjd-user
      - FILE_MYJD_PASSWORD=myjd-pass
      - MYJD_DEVICE_NAME=jdownloader@MY_COMPUTER
    volumes:
      - jdownloader2/config:/opt/JDownloader/app/cfg
      - download//jdownloader2:/opt/JDownloader/Downloads
      - /etc/localtime:/etc/localtime:ro
    secrets:
       - myjd-user
       - myjd-pass
    restart: unless-stopped

secrets:
  myjd-user:
    file: jdownloader2/secrets/myjd_user.txt
  myjd-pass:
    file: jdownloader2/secrets/myjd_pass.txt

The folder structure :

.
├── docker-compose.yml
├── download
│   ├── jdownloader2
├── jdownloader2
│   ├── config
│   └── secrets
│       ├── myjd_pass.txt
│       └── myjd_user.txt