secrets.nix: Remove age secrets management

flake.lock

@@ -1,26 +1,5 @@
 {
   "nodes": {
-    "agenix": {
-      "inputs": {
-        "darwin": "darwin",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1682101079,
-        "narHash": "sha256-MdAhtjrLKnk2uiqun1FWABbKpLH090oeqCSiWemtuck=",
-        "owner": "ryantm",
-        "repo": "agenix",
-        "rev": "2994d002dcff5353ca1ac48ec584c7f6589fe447",
-        "type": "github"
-      },
-      "original": {
-        "owner": "ryantm",
-        "repo": "agenix",
-        "type": "github"
-      }
-    },
     "bij": {
       "inputs": {
         "nixpkgs": [
@@ -59,28 +38,6 @@
         "url": "https://git.clerie.de/clerie/chaosevents.git"
       }
     },
-    "darwin": {
-      "inputs": {
-        "nixpkgs": [
-          "agenix",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1673295039,
-        "narHash": "sha256-AsdYgE8/GPwcelGgrntlijMg4t3hLFJFCRF3tL5WVjA=",
-        "owner": "lnl7",
-        "repo": "nix-darwin",
-        "rev": "87b9d090ad39b25b2400029c64825fc2a8868943",
-        "type": "github"
-      },
-      "original": {
-        "owner": "lnl7",
-        "ref": "master",
-        "repo": "nix-darwin",
-        "type": "github"
-      }
-    },
     "fernglas": {
       "inputs": {
         "flake-utils": "flake-utils",
@@ -299,7 +256,6 @@
     },
     "root": {
       "inputs": {
-        "agenix": "agenix",
         "bij": "bij",
         "chaosevents": "chaosevents",
         "fernglas": "fernglas",