Add a package maintainability score

[vtsykun]

When searching for a package it would be nice to see a rating/score index of how the package is actively maintained. For example, this value can be calculated based on the date of the last release and commit, the response time per issue and other GitHub API data. Currently, when searching for a package, the most popular package is not always good and this can leads to package selection errors, like here symfony/symfony#49831

[Spomky]

I agree with this idea. It would be very nive to spot unmaintained or outdated libraries 👍🏽.

[zerai]

https://isitmaintained.com/#metrics

[Seldaek]

Yeah this may be something, but it is IMO really hard to do this automatically in a sensible way that will work for everything. And it's also possibly a lot of work, so definitely not gonna be top of the list.

[94noni]

PR as discussion draft opened here #1410
Feel free to comment :)