feature: backup command to backup secrets and LN recovery files

[0xB10C]

Some secrets and important recovery files, like e.g. CLNs hsm_secret and emergency.recover, aren't generated and managed by generateSecrets. A user needs to back these up manually.

It would be good to have a backup command similar to the deploy command in the nix-shell. This would copy existing secrets from the node to the host. This command can be mentioned in the documentation and in the example configuration.nix next to e.g. services.clightning.enable = true;. Also, an automatic backup step run after deploy is a possibility. Would be good if it could reuse the krops target to connect to the node, if possible.

relevant files:

• Core LN:
  • emergency.recover
  • hsm_secret
• LND:
  • Static Channel Backups
• ...