FEAT #11779 TIME 5 add indexing page skeleton

src/frontend/app/app-routing.module.ts

src/frontend/app/app.module.ts

src/frontend/app/indexation/indexation.component.html

src/frontend/app/indexation/indexation.component.scss

src/frontend/app/indexation/indexation.component.ts

...app/indexation/indexing-form/indexing-form.component.html

...app/indexation/indexing-form/indexing-form.component.scss

...d/app/indexation/indexing-form/indexing-form.component.ts

src/frontend/app/menu/menu-shortcut.component.ts

src/frontend/service/header.service.ts