Restore from legacy backup

When you provision an app for the first time, it could be a migration of a legacy app installed in a virtual machine or a docker host.

Also you may want to start it with volumes content already containing datas.

this feature will simply :

• add an argument to 'provision' command
• this argument will a full path (filesystem at first) to a tar file containing each volume data in its respective targe directory.
• libre.sh will simply untar this file in the app directory without any other check or actions.

as an example

the nextcloud app has several volumes but all data is in 2 dirs and nginx conf)

the tar file as argument can contains for example :

___ /data -> Corresponding to the legacy /var/ww/html

___ /mysql -> Corresponding to the legacy /va/lib/mysql

With this tar file you can easily script the migration of old apps in Virtual Machines to libre.sh

Task list

• Start with Piwigo a script that would backup an installed app on a linux VM or LXD( now in utils/backup_app.sh and restore_app.sh )
• adapt the script for prestashop and any other app