improve UX and useability for Settings and prefernces for mobile and desktop (#200)

frontend/src/App.jsx

frontend/src/components/AdminSidebar/index.jsx

frontend/src/components/Modals/Settings/Appearance/index.jsx

frontend/src/components/Modals/Settings/VectorDbs/index.jsx

frontend/src/components/Modals/Settings/index.jsx

frontend/src/components/Sidebar/SettingsOverlay/index.jsx

frontend/src/components/Sidebar/index.jsx

frontend/src/pages/Admin/Appearance/index.jsx

frontend/src/utils/paths.js