Docker volume changes

[diegogslomp]

The /usr/local/samba volume should be replaced by three volumes: /usr/local/samba/etc, /usr/local/samba/private and /usr/local/samba/var, as only these folders should be persistent.

To keep data from the old volume, mount /usr/local/samba to /mnt/samba and copy the folders to the new volumes:

cp -rf /mnt/samba/etc /usr/local/samba
cp -rf /mnt/samba/private /usr/local/samba
cp -rf /mnt/samba/var /usr/local/samba