feat: add onboarding with oldmarr import (#1606)

packages/old-import/src/prepare/prepare-sections.ts

@@ -0,0 +1,13 @@
+import type { OldmarrConfig } from "@homarr/old-schema";
+
+import { mapCategorySection, mapEmptySection } from "../mappers/map-section";
+
+export const prepareSections = (
+  boardId: string,
+  { categories, wrappers }: Pick<OldmarrConfig, "categories" | "wrappers">,
+) =>
+  new Map(
+    categories
+      .map((category) => [category.id, mapCategorySection(boardId, category)] as const)
+      .concat(wrappers.map((wrapper) => [wrapper.id, mapEmptySection(boardId, wrapper)] as const)),
+  );