Use import maps

[niklasmohrin]

Javascript / Typescript imports are a bit weird sometimes, for example you have to import from .js files when in a .ts file. Additionally, we currently use the support_js_module_import_aggregation option of Django's ManifestStaticFilesStorage to change the imports of javascript files we serve so that they use a filename with a hash in it (this avoids fetching a cached, outdated file).

However, there is also a builtin feature: Import maps. This way, we could switch out utils.js for utils and also ensure that we are using the same version of a file everywhere.

A nice bonus: Currently, all files including foo.js need to be updated when the hash of foo.js changes and therefore also get a new hash and will not be cached anymore. This will not happen anymore with import maps.