admin-ui: Modify the structure of top navbars

A navbar has been added with the breadcrumb and the details' subnav.
admin-ui: Update design and style of navigation bars
admin-ui: Remove arrow-pointer and modify style of nav-menus
admin-ui: Unify dropdown lists
admin-ui: Add home top-menu
admin-ui: Update sidebar style
Merge branch 'feature-admin-ui-bars' into feature-admin-ui-style