Automate feature support data updates

[mathiasbynens]

For the feature support listings on v8.dev/features, we started small and shipped a manually maintained version. The maintenance overhead is acceptable, since once a feature ships in any one environment, we can update our feature support listing, and then we (generally) never have to update that specific feature+environment entry again.

However, it would be nice to automate this whole thing, and use a centralized data source like ChromeStatus, CanIUse, or MDN.

[mathiasbynens]

cc @RReverser

[mathiasbynens]

Per https://twitter.com/floscholz/status/1171147561098518530, MDN might offer embeds soon. Still, we'd likely want to use the data directly at build time, and turn it into HTML, reducing the need for third-party HTTP requests.

[camillobruni]

Declaring bug-bankruptcy after >4 years of inactivity.