defaults.retention-count and defaults.retention-age are not applied

[schakko]

In backup definition documentation it is described that the following configuration is allowed:

'./databases/{{client}}':
  defaults:
    retention-count: 10
    retention-age: 7d

But that configuration does not have any effects on Prometheus metrics backmon_backup_file_count_aim and backmon_backup_file_age_aim_seconds (also probably backmon_backup_latest_creation_aim_seconds).
retention-count and retention-age can only be directly applied below the files: section.

Either change the documentation or change the behavior.

I've added a reference to this task in backup definition documentation. It must be remoed after we have decided how to deal with this issue.

[thomashoell]

In https://github.com/dreitier/backmon/blob/main/storage/storage.go#L307 only the file definitions are taken into account. To fix this, the defaults need to be passed down to the files section if the corresponding parameters (retention age/count) are not set.