backwards: Add secret for restic

secrets/backwards/restic-password.age

@@ -0,0 +1,7 @@
+age-encryption.org/v1
+-> ssh-ed25519 Pu0HWg qmcWFPndrhXlpjBtSsVNARAOHM9UNtfcEvtSGx/BLHY
+EdnzUWju9g61idxWmDaaxSZ6ZiVvhFLOKH3hY1Kyk8s
+-> ssh-ed25519 +oNaHQ CMBvVWHwVsY89rbdYvVoVeoZlIXLJoIN8xsoqqBnSiA
++xogVU/MBezQzq1rbIOqT5PGNYqM8o0Pmojk2npqT4U
+--- mdhPf3weI9cOcaAh9j/CVB+KRfPSRuT678oueeJjdCk
+ZñmݹÿÅÓº*ˆŒ9kÀw¶N¯Zh&ÈGô␍ßkÞÀºÆŸþŸA#ª“�lù u¤Q
ôïù—›ÛîTԟטŽ²Ž,ßC�V3†Äµ”

secrets/secrets.nix

@@ -33,6 +33,7 @@ in {
   "backwards/root.backwards.pub.age".publicKeys = [ backwards alex ];
   "backwards/syncthing-cert.age".publicKeys = [ backwards alex ];
   "backwards/syncthing-key.age".publicKeys = [ backwards alex ];
+  "backwards/restic-password.age".publicKeys = [ backwards alex ];
   "backwards/alex.backwards-codeberg.org.age".publicKeys = [ backwards alex ];
   "backwards/alex.backwards-codeberg.org.pub.age".publicKeys = [ backwards alex ];
   "backwards/wpa_supplicant.conf.age".publicKeys = [ backwards alex ];