Extract snackbar error message implementation to service (#42)

Co-authored-by: Phan Huy Tran <p.tran@neusta.de>
Reviewed-on: http://git.simonis.lol/angular/ems-frontend/pulls/42
Reviewed-by: Constantin Simonis <constantin@simonis.lol>

src/app/services/error.handler.service.ts

@@ -0,0 +1,18 @@
+import {inject, Injectable} from '@angular/core';
+import {MatSnackBar} from "@angular/material/snack-bar";
+
+@Injectable({
+  providedIn: 'root'
+})
+export class ErrorHandlerService {
+  private readonly snackBar: MatSnackBar = inject(MatSnackBar);
+
+  public showErrorMessage(message: string): void {
+    this.snackBar.open(message, 'Close', {
+      duration: 5000,
+      horizontalPosition: 'end',
+      verticalPosition: 'bottom',
+      panelClass: ['!bg-red-50', '!text-red-900', '!border', '!border-red-100']
+    });
+  }
+}