Update dashboard: Use static files

[larswmh]

This PR prepares the dashboard to use static files when data can't be fetched from TSI anymore.

Final ToDos:

• [ ] Replace on May 31st, 2023 (once the data for the day has been pushed)
• src/data/analyse-data.json with TSI json file
• src/assets/dashboard/cwa_all_data.zip with TSI zip file
• src/assets/dashboard/cwa_downloads_data.zip with TSI zip file
• src/assets/dashboard/cwa_ppa_warnings_data.zip with TSI zip file
• src/assets/dashboard/cwa_sharing_data.zip with TSI zip file
• src/assets/dashboard/test_results_data.zip with TSI zip file
• [ ] src/assets/js/analyse/date.js + src/assets/js/analyse/picker.js: Change const now to DateTime.fromISO("2023-05-31"), as keeping the option for any dates before will become obsolete. We're keeping it there for testing purposes until then.

---

Internal Tracking ID: EXPOSUREAPP-14768

[MikeMcC399]

@larswmh

The dashboard data has not been updated since May 2, 2023. Has the data-feed already shut down?

In any case the only new data from May 1, 2023 could be from downloads, as the other functionality concerning tests and warnings was already shut down on April 30, 2023.

[dsarkar]

@MikeMcC399 Indeed, no new data was provided since May 1, except download numbers. On May 2 the json file was updated one last time, but only download numbers have been added.