modules.settings->shared: renamed mine.settings to mine.shared.settings

Allows to use it with other things, such as ...

mine.shared.lib
mine.shared.meta
mine.shared.settings

shared/modules/default.nix

@@ -1,6 +1,6 @@
 {
   imports = [
-    ./settings.nix
+    ./shared.nix
 
     ./zrepl.nix
     ./disko.nix

shared/modules/shared.nix

@@ -1,7 +1,7 @@
 { lib, ... }:
 
 {
-  options.mine.settings = lib.mkOption {
+  options.mine.shared.settings = lib.mkOption {
     type = lib.types.attrsOf lib.types.anything;
     default = {};
   };