Resources drop down menu on a navigation bar

[LeYun920]

This pull request introduces a new Resources dropdown menu to the application’s navigation bar. The dropdown provides quick access to useful JHipster resources.

Changes Made:

• Edited src/main/webapp/app/layouts/navbar/navbar.component.html to include a new nav-item dropdown.
• Added two external links within the dropdown:
• Website – links to https://www.jhipster.tech/
• JDL Studio – links to https://www.jhipster.tech/jdl/
• Configured links to open in a new browser tab (target="_blank").

UI Impact:

• Navbar Update:
• A new "Resources" menu appears in the navbar.
• Clicking the dropdown displays two resource links for quick navigation.

No backend changes were made. This update only affects the UI layout for the navbar.