No strict backup rules

[agoncharov-reef]

The situation with backups is not good. Nobody checks whether they actually work (i.e. whether they are created, and whether whatever is created is good for restoring after failure), and we have only small section in README about backups

Proposal:

1. Add strict policy for backing up each new project (script backup, cloud service snapshots, backup images rotation policy, b2-or-not-b2 etc)
2. Add backups creation stats to grafana, set up alerts if backups are missing
3. Add periodic checks that backups are usable
4. Check all existing projects for all clients and ensure all is fine