Refactor tutorial service for public access and enhance authentication handling

jambotron-ui/src/app/components/tutorials.component/tutorials.component.ts

@@ -36,14 +36,14 @@ export class TutorialsComponent {
   // }
 
   retrieveTutorials(): void {
-    this.tutorialService.getAll()
-      .subscribe(
-        data => {
-          this.tutorials = data;
-          console.log(data);
-        },
-        error => {
-          console.log(error);
-        });
+    this.tutorialService.getAllPublic().subscribe(
+      (data : Tutorial[]) =>{
+        this.tutorials = data;
+        console.log(data);
+      },
+      error => {
+        console.log(error);
+      }
+    );
   }
 }