- Add an update button in the About page which links to the Github Releases page
- Display if there is a new version available in the About page
- Display an error if the request to Github failed

The request is done asynchronously, each time you press on the About button
The message checking updates... is displayed in the meantime.

Parallelizing tasks with Iced Commands can be tricky because there is no `join` feature.

This commit simplifies all the init logic (download UAD list, get devices info, load packages) and fix a concurrency issue where
a tasks could be starting when it should have waited for another task to finish.

Add a state for the `List` module: `Ready` or `Loading(LoadingState)`

Asynchronously check for updates and display a button update instead of the `Apps` button if an update is available

Update process:
- Download the right release based on the current file name (temp_<release_name>)
- Extract the executable from the tarball for Linux and MacOS release
- Rename the current executable to a temp path and rename the new version as the original file name
- Spawn a new process to run the new (renamed) executable and kill the current one
- Remove the old executable

 `self-update` is a new default cargo feature. It can be disabled with the `--no-default-features` flag.