Backup-Restore functionality

[demonfiddler]

Need to be able to backup and restore the entire database contents. We could quite possibly leverage MariaDB's native CSV import/export capability. Envisaging that the backup set might consist of a ZIP file containing one CSV file per table, which could be individually source-controlled if necessary. Open questions:

1. Whether to support incremental backup/restore. This would be a lot tricker to implement as it would require record-level 'last-changed' and 'last-backed-up' metadata in order to identify which records to include, Incremental restore would potentially require rollback to that point in the backup set.
2. There would also need to be a means to detect incoming duplicates and a means to map incoming keys to existing keys.
3. Supporting only full backup/restore would be simpler, as when restoring one could delete all records, reset sequences to zero, and simply import the records verbatim, using the original keys. Would this be technically feasible and would there be any need to reconcile old and new keys in order to maintain referential integrity.
4. Users and groups would be problematic to restore, since: a.) the records are continually required in order to support authentication and authorization and b.) user records are involved in foreign key relationships with tracked entities.