boreal: get rid of git crypt secrets for this host

Also move to restic-backup

modules/secrets/restic-backup/boreal-credentials.age

@@ -0,0 +1,10 @@
+age-encryption.org/v1
+-> ssh-ed25519 YWMQkg B5tQXcUdu751YYA4Y8uRH/DgGDi24AsXEAKkCVfg+Ro
+21Gz0MsMCtWzUdVuaWdNwEU9Ts8lOQWCd7Ejf2tkxks
+-> ssh-ed25519 k2gHjw NIG04WnNgq5bnSl9KmvFyvpGdFlmOFtXzuYtrsFOKXM
+ZYZVyIM0jnhguRmfIpRtFg0StgYTlu/P9bgxBy9dbOg
+-> u5-grease
+MTgqDb6tqCuvdlXj9c2Y3XX1X7JfrdeKLM0EQ75ZJe+Hrntnpvn4fSlBr8QoOahm
+fg
+--- VzgNZ3/IBQVeYfOMGjnHPDRKoBDdxHth61pevk5+fLw
+ŒÙúDíï°	´&…<QØ+¨úþ‹éJoTÇ;US9.©âu'v¸œ,‘Ä@“úÿQKcë‚ÛzÑ>v¢€ÃN1›±tòÚ8›w<˜Îò“w­°d<C2B0><64>>s:µG_øæÆšyø„u,þÅ%@J hñ"†Ev‡ÙX

modules/secrets/secrets.nix

@@ -11,6 +11,8 @@ let
   all = users ++ machines;
 in
 {
+  "restic-backup/boreal-password.age".publicKeys = [ alarsyo boreal ];
+  "restic-backup/boreal-credentials.age".publicKeys = [ alarsyo boreal ];
   "restic-backup/zephyrus-password.age".publicKeys = [ alarsyo zephyrus ];
   "restic-backup/zephyrus-credentials.age".publicKeys = [ alarsyo zephyrus ];