Register the activity properly and create a scoped element if the API is there.

One all bugs are fixed upstream this should allow us to switch to lit v2
without any further changes.

In newer versions there is now a normal method for this which also supports
dynamically added components.

The static version is deprecated and removed in 2.0, so we need to port here.

Include the highlight.js css in all activities and move the
code css into the app, so it's defined where it is used.

This has proper support for rollup while providing the same API.

This is what open-wc recommends now and uses in their @open-wc/testing package

FileHandlingClipboard and FileSink depend on each other. Register
the later at runtime so we don't get a dependecy cycle for imports.

Remove duplicated clipboard warning, disable nextcloudfilepicker upload button if no files are selected

Otherwhise it will try to access it an error out when trying to open
the dialog.

Importing the module itself adds a dependency on teh index which creates a cycle.
Reference the internal file instead.

Move pushEvent inside MatomoElement, make sure event name is non-empty string and add extra handling for TypeError