refactor: system metadata (#8923)

refactor(server): system metadata

server/src/dtos/system-metadata.dto.ts

@@ -0,0 +1,15 @@
+import { IsBoolean } from 'class-validator';
+
+export class AdminOnboardingUpdateDto {
+  @IsBoolean()
+  isOnboarded!: boolean;
+}
+
+export class AdminOnboardingResponseDto {
+  isOnboarded!: boolean;
+}
+
+export class ReverseGeocodingStateResponseDto {
+  lastUpdate!: string | null;
+  lastImportFileName!: string | null;
+}