Improve warning and missing reports for Radarr connections

[Bothari]

Description

Radarr uses a different method of reporting "missing" content, which tracks the availability of the items. Before this change, the Radarr service would display "missing" count for movies which are years away from release. With this change, it will now only display "missing" count for movies which have been released and should be available per the user settings defined in Radarr.

I also improved the "warning" handling to include queue warnings and errors. For example if a movie download has stalled for some reason, it will show the warning.

Fixes #638, "Add Wanted count to Arrs" https://github.com/bastienwirtz/homer/issues/638

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [X] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [X] I've read & comply with the contributing guidelines
• [X] I have tested my code for new features & regressions on both mobile & desktop devices, using the latest version of major browsers.
• [X] I have made corresponding changes to the documentation (README.md).
• [X] I've checked my modifications for any breaking changes, especially in the config.yml file