packages: Implement diagnose() method for Packages component

Packages component was added in !2130 (closed) with all the relevant apps using this component. Implement a diagnose() method for this component that would show the up-to-date status of the Debian packages involved. Iterate through the list of packages, for each package check if the Debian package is up-to-date and produce a diagnostic result that is either 'success' or 'warning'. Including the diagnostic test message the name and latest expected version of the Debian package.

This is an alternate implementation for the MR !1399 (closed).