Expand compat features with a lock file

[ddbeck]

Referencing compat features will be cumbersome for very large feature groups (e.g., the Temporal API). We ought to have a way to both a) reference many features with a small notation (e.g., Temporal.*) and b) ensure the stability of the features selected (i.e., do not automatically vacuum up all future features).

Philip suggested a lockfile approach, which sounds quite manageable:

I think we'll need wildcards or some way to list an interface with all of its members, but still notice when we update BCD if the list of matched features changes. One way to think about that is like a lockfile, where we put both the simple-ish input and the expanded output under source control, and ensure they stay in sync through CI.

Originally posted by @foolip in #93 (review)

[ddbeck]

Since #787, we have dist files which take in tags from BCD (the lockfile approach). Since #1227, we have compute_from which allows us to take in new items without necessarily accepting them for the headline status. I think this is done.