Raveberry

- Big visualization rework:
* Visualization is more robust and more performant
* A Pi 4 can comfortably render HD30fps, before performance always degraded significantly
* Switched library from [pi3d](https://github.com/tipam/pi3d/tree/master/pi3d) (Python) to [glium](https://github.com/glium/glium) (Rust)
* Moved the code into its own repository: [https://github.com/raveberry/visualization](https://github.com/raveberry/visualization)
* Optimized for tile-based GPUs: render directly to framebuffer, smaller and less complex shaders, less draw calls, moved computation to the CPU
* Programs are loaded dynamically, new shaders will show up as new programs
* UPS and resolution can be can be configured in `/lights`
* X resolution is adjusted to adapt to performance fluctuations
* Instead of a white xterm, the Raveberry logo is shown when no screen program is active
* Added new screen program that loops through a colored Raveberry logo
* Removed old code and dependencies
* Hide programs that require cava if it is not installed

- Raveberry exits explicitly when restarting. Sometimes, it needed to wait for a timeout, now restarts are much faster.
- Task strategy can be switched between celery and threads for low memory devices

- Visualization is possible from docker setup
- Added environment variable for docker setup to deal with CSRF issue
- Host and IP for all services can be set via environment variables
- Merged `icecast.docker-compose.yml` and `docker-compose.yml`, only the latter one exists now
- `MOPIDY_OUTPUT` can now contain slashes, e.g. for paths of filesinks

- Created dedicated resources folder for images/videos/sounds
- `raveberry system-install` is now just `raveberry install`
- Added `raveberry install --use-default-password-i-promise-ill-change-it` to allow easier scripted installs
- Move to actively developed PCA library for the led strip
- Problematic python dependencies are forced to be install from wheels, speeding up installation
- Install cava from apt instead of building from source, speeding up installation
- Simplified cava config
- Changed message when there are no hashtags
- Removed unused scripts
- Buzzer cooldown is a float
- Ansible warning silenced

- Restructured code into a backend folder to clean up the root folder
- Added link to new discord server into readme
- Debug setup uses threads instead of celery, speeding up reload significantly
- Docker images are tagged with the version
- Lights worker flushes the settings cache before loading settings. Program changes apply immediately.

- Big suggestion improvements:
* Trigram similarity is used instead of full text search
* Now Raveberry can provide suggestions for substrings, stop words (and, a, the etc.) and typos
* This is slower, but GIN indexes and config tweaking minimize overhead

- Song metadata is cached in the database. Suggestions are now faster than before, despite the slower query.
- Directly after the update, durations are shown incorrectly. Either wait until metadata is synced automatically overnight, or run:
- `sudo -u www-data python3 /opt/raveberry/manage.py syncsongmetadata`

- Upgraded to Django 4.0. This was necessary to use functional indexes.
- Django 2.2 would be out of support soon anyway, so now was a good time.
- Python 3.8 or higher is now required.
- The main reason for not upgrading was that multiple asgi-requests could not be processed in parallel since Django 3.0.
- In 4.0, context-aware `sync_to_async` removes this issue, finally allowing the upgrade without usability impact.

- When checking whether voting is allowed on server side, a redis transaction is used to reduce performance impact.
- Settings are cached for a short time, removing load from tasks that query settings often when they change very rarely.
- Only some instead of all urls are used to measure activity (page loads, voting and musiq requests) to decrease performance impact.

- Switched from youtube-dl to yt-dlp, significantly increasing download speed.

- Fixed bug where color definitions got lost in the css minification process
- Tapping an "error" suggestion does nothing
- Buttons for queue control are further apart (and thus harder to mis-select)

- Suggestions are much more responsive:
* The first line (the query itself) is shown immediately
* Offline suggestions are shown as soon as they are ready and don't wait for the online suggestions
* Placeholders for online suggestions until they are available
* Different platforms (e.g. Youtube and Spotify) are queried in parallel

- Increase dhcp ip range for hotspot
- Bluetooth scanning and connecting does not spit a huge error anymore. Cause was that requests were sent twice.
- Song duration is shown in song info modal. Current song duration can now be determined
- Ring visualization improved
- The Raspberry Pi's internal pwr led (red) is disabled when the ring is active
- The internal act led (green) indicates active Raveberry requests

- Add option for server-side vote duplication checking by IP
- Use session keys instead of IPs to link requests logs
- Most active device entry is sorted correctly in analysis section
- Page does not scroll on mobile after clearing the input field
- Old hashtag doesn't start scrolling when adding a new one
- Correct QR code is shown for hotspot wifi on `/network-info`
- Improve documentation for remote feature
- Pin postgres version in docker-compose files
- Admin page in docker container looks fine now