We can not have sysmocom-backup-default and sysmocom-backup-data-default
installed at the same time. I don't want to play games with RREPLACE and
RPROVIDES either. So simply use one of the two files. Copy the two more
default values over to the other recipe.
Move the default file list to a separate file in /etc/sysmocom/backup.d,
which is itself included in the backup. Also create a symlink to the
most recent backup.
Creating a new file in /etc/sysmocom/backup.d/ that ends with .backup
will be read during the backup and then be restored. This way we can
easily extend the files to backup.
* when restoring links e.g. for systemd files
the links will be created with content// prefix
* use transform instead of strip to remove
the "content/" prefix
* bump PR
Additional applications might store files in /etc/default and it
is the easiest to backup up all of them. This has the danger that
after an upgrade the default file is not compatible/optimal but
we will need to deal with that once it occurs.