move file system utils to file-system module

src/Umbraco.Web.UI.Client/src/packages/core/file-system/index.ts

@@ -0,0 +1,2 @@
+export * from './append-file-extension.function.js';
+export * from './server-path-unique-serializer.js';

src/Umbraco.Web.UI.Client/src/packages/templating/utils/index.ts

@@ -51,5 +51,3 @@ export const getUmbracoFieldSnippet = (field: string, defaultValue: string | nul
 };
 
 export * from './parent-path-from-server-path.function.js';
-export * from './server-path-unique-serializer.js';
-export * from './append-file-extension.function.js';