Allow to create labels directly from Manage labels page. It uses the same fullscreen dialog style as adding other things.
Almost all of the code is reused the `NewTeam` component
Co-authored-by: David Košťál <kostal.david8@gmail.com>
Reviewed-on: vikunja/frontend#359
Reviewed-by: konrad <konrad@kola-entertainments.de>
Co-authored-by: profi248 <kostal.david8@gmail.com>
Co-committed-by: profi248 <kostal.david8@gmail.com>