lib/modules: Add a function to create an option alias that respects the priority

This commit adds a function `mkAliasOptionModuleWithPriority`.  This
function will make an alias to an existing option and copy over the
priority.

This functionality is needed for PRs like #53041.  In that case
`nixos-generate-config` added an option to `hardware-configuration.nix`
with `mkDefault`.  That option was then changed and an alias created for
the old name.

The end user should be able to set the non-alias option in their
`configuration.nix` and have everything work correctly.  Without this
function, the priority for the option won't be copied over correctly
and the end-user will get a message saying they have the same option
set to two different values.

lib/tests/modules/alias-with-priority.nix

@@ -32,7 +32,7 @@ with lib;
 
   imports = [
     # Create an alias for the "enable" option.
-    (mkAliasOptionModule [ "enableAlias" ] [ "enable" ])
+    (mkAliasOptionModuleWithPriority [ "enableAlias" ] [ "enable" ])
 
     # Disable the aliased option, but with a default (low) priority so it
     # should be able to be overridden by the next import.