[Feature] Include stats file with backups

[hazzuk]

Prerequisites

• I have searched for duplicate or closed feature requests

Proposal

When a backup is created, a backupdate.txt stats file should be included within the archive.

Should include information about

• the backupdate version
• script variables used to create the backup
• docker stats, like the version and id of the docker images

Motivation and context

When restoring from backups, this data should be assumed to be unknown and so may prove useful.