feat(theme-shared): create nav item utility functions

npm/ng-packs/packages/theme-shared/src/lib/utils/index.ts

@@ -1,3 +1,4 @@
-export * from './widget-utils';
 export * from './date-parser-formatter';
+export * from './nav-items';
 export * from './validation-utils';
+export * from './widget-utils';

npm/ng-packs/packages/theme-shared/src/lib/utils/nav-items.ts

@@ -0,0 +1,22 @@
+import { Type } from '@angular/core';
+import { ReplaySubject } from 'rxjs';
+
+export interface NavItem {
+  component?: Type<any>;
+  html?: string;
+  action?: () => void;
+  order?: number;
+  permission?: string;
+}
+
+const navItems: NavItem[] = [];
+const navItems$ = new ReplaySubject<NavItem[]>(1);
+
+export function addNavItem(item: NavItem) {
+  navItems.push(item);
+  navItems$.next(navItems.sort((a, b) => (a.order ? a.order - b.order : 1)));
+}
+
+export function getNavItems() {
+  return navItems$;
+}