Turning the "importsNotUsedAsValues" TS config value to "error".
This will require us to use `import type` instead of `import` when we are importing a value that is only used as a type (and therefore that is dropped by the Typescript compiler).
Why this change?
This is a requirement to be able to use Svelte in the future. See https://github.com/sveltejs/svelte-preprocess/issues/206#issuecomment-663193798
In "alone" mode (or single-player mode), WorkAdventure does not connect to the server at all.
In order to enter the "alone" mode, you need to add "?alone=true" to the URL.
"alone" mode can be useful for tutorials (First Time User Experience) where you want to explain how WorkAdventure works without being disturbed by other users.