As we use cookies for the game and that localStorage is only used to save the
theme set on the start page, it isn't needed to use it, as the dark theme would
be set as a fallback.
In order to show a cookies requirement message if they are disabled, we need to
remove the one of the localStorage, as when cookies access is disabled,
localStorage cannot be accessed.
These interactions are checks of nickname and room code validity, where it is
relevant.
Also set a maximum room code length to 20 characters, at least for now.
Some changes in the existing code have been also made to avoid code duplication
and fix some issues.
Co-authored-by: Cazals Mathias <mathiascazals@users.noreply.github.com>
