Ubo-app

- feat: update menu showing current version and a button to update ubo-app
- feat: add update system service to automatically install an update in boot time if it is already downloaded
- feat: add install script
- feat: setup polkit to let `ubo` user `reboot` and `poweroff`
- refactor: improve `deploy.sh` so that it hasn't a hardcoded username
- feat: assume the package is installed in `/opt/` instead of `/home/pi/`
- refactor: move service related files in `store/` to `store/services/`
- refactor: update to latest versions of `ubo-gui` and `python-redux`

- refactor: make `create_task` functional for the main application just like its services

- feat: 16 add volume chime
- fix: 16 set the default pulseaudio device to "wm8960-soundcard"

- fix: 16 use a logarithmic scale for volume

- feat: 16 connect to the audio controller, play chimes for notifications

- feat: 15 add `rgb_ring` service and use it for notifications