Add sops and setup sops-nix

We want to store secrets, and due to the shortcomings of git-crypt (not
working, not being able to push to public caches, etc.) we have decided
to use sops.

Change-Id: I9ed38a93879ca5ff4a452e6e8017b500a4d2cbb6
Reviewed-on: https://git.clicks.codes/c/Chimera/NixFiles/+/414
Tested-by: Skyler Grey <minion@clicks.codes>
Reviewed-by: Skyler Grey <minion@clicks.codes>
diff --git a/flake.lock b/flake.lock
index 26198c8..d58bd9d 100644
--- a/flake.lock
+++ b/flake.lock
@@ -235,6 +235,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1708210246,
+        "narHash": "sha256-Q8L9XwrBK53fbuuIFMbjKvoV7ixfLFKLw4yV+SD28Y8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "69405156cffbdf2be50153f13cbdf9a0bea38e49",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-23.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs_2": {
       "locked": {
         "lastModified": 1707546158,
@@ -251,6 +267,22 @@
         "type": "github"
       }
     },
+    "nixpkgs_3": {
+      "locked": {
+        "lastModified": 1708151420,
+        "narHash": "sha256-MGT/4aGCWQPQiu6COqJdCj9kSpLPiShgbwpbC38YXC8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6e2f00c83911461438301db0dba5281197fe4b3a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nur": {
       "locked": {
         "lastModified": 1707853532,
@@ -275,7 +307,8 @@
         "nix-index-database": "nix-index-database",
         "nixpkgs": "nixpkgs_2",
         "nur": "nur",
-        "snowfall-lib": "snowfall-lib"
+        "snowfall-lib": "snowfall-lib",
+        "sops-nix": "sops-nix"
       }
     },
     "snowfall-lib": {
@@ -300,6 +333,25 @@
         "type": "github"
       }
     },
+    "sops-nix": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_3",
+        "nixpkgs-stable": "nixpkgs-stable"
+      },
+      "locked": {
+        "lastModified": 1708500294,
+        "narHash": "sha256-mvJIecY3tDKZh7297mqOtOuAvP7U1rqjfLNfmfkjFpU=",
+        "owner": "Mic92",
+        "repo": "sops-nix",
+        "rev": "f6b80ab6cd25e57f297fe466ad689d8a77057c11",
+        "type": "github"
+      },
+      "original": {
+        "owner": "Mic92",
+        "repo": "sops-nix",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1689347949,