feat: add Master Admin application functionality

src/app/core/services/loading.service.ts

@@ -0,0 +1,24 @@
+import { Injectable, signal} from '@angular/core';
+
+@Injectable({
+  providedIn: 'root',
+})
+export class LoadingService {
+
+  private requestCount = 0;
+  readonly isLoading = signal(false);
+
+  show(): void {
+    this.requestCount++;
+    this.isLoading.set(true);
+  }
+
+  hide(): void {
+    this.requestCount--;
+
+    if (this.requestCount <= 0) {
+      this.requestCount = 0;
+      this.isLoading.set(false);
+    }
+  }
+}