Raveberry

- Added song cooldown option that prevents a song from being enqueued again for a given time
- Added buzzer success probability option. Custom sounds can be provided in `resources/sounds/yes` and `resources/sounds/no`.
- Dropdown icons have descriptions
- Removed link to /stream from dropdown
- Added button to send feedback
- Moved "Delete Current Song" button to Queue Control, which is available on docker setup
- Visualization correctly works on big screens. Previously, a scaling would lead to an only partially visible visualization.
- Prevent hashtag scrolling for distances < 1 pixel
- Fixed bug where the is-service-active check would crash for uninstalled services
- Do nothing if the currently active task strategy is requested

- Hotspot status shows whether it would start without homewifi instead of whether it is currently enabled
- Changed message when no online suggestions are returned
- Each section in settings can be collapsed, making them much more usable
- PYTHONOPTIMIZE set to 1. pycparser has problems with level 2.

- Refactoring: mypy and pylint run without complaining
* Simplified control flow, added type hints, sorted imports, etc.
* Added instructions to CONTRIBUTING.md

- Reordering songs works from mobile devices
- The host that is used to check internet connectivity can be configured
- New music only mode: removed suggestions for playlists, no "Error" suggestions are shown
- manage.py celery is now manage.py startcelery
- celery module renamed, update your docker-compose.yml. systemd service is updated automatically
- Sites other than `/musiq` are not tracked for user activity anymore
- Filepaths are quoted, allowing for more obscure filenames in the local library (126)
- PYTHONOPTIMIZE is set in production, stripping docstrings and skipping asserts

- Include resources folder in PyPi package

- 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.