Refactor top bar to use modular css

frontend/package.json

frontend/src/components/App.scss

frontend/src/components/atoms/NavBarTabItem/index.tsx

...tend/src/components/atoms/NavBarTabItem/style.module.scss

frontend/src/components/molecules/NavBarBrand/index.tsx

...nd/src/components/molecules/NavBarBrand/style.module.scss

frontend/src/components/molecules/NavBarTabGroup/index.tsx

...src/components/molecules/NavBarTabGroup/style.module.scss

frontend/src/components/organisms/TopBar/index.tsx

frontend/src/components/organisms/TopBar/style.module.scss

frontend/src/components/pages/.gitkeep

frontend/src/scss/custom.scss