Project: nuxt
Task (challenging): 1) Add a component in components/HeaderUserMenu.vue:
   - If not logged in, display a button (.header-go-login) that navigates to /login
   - If logged in, display the username (.header-username) on the right side of the site header
2) If user is logged in, when the .header-username is hovered, show a dropdown menu with:
   - A button (.header-logout-btn) for logging out
   - A button (.header-go-user-profile) for navigating to the current user's profile page
3) Add Style to beautify UI
4) DO NOT use a third-party UI library