Add script to migrate features to BCD tags

[queengooborg]

This PR is a continuation off of #473, which adds a script that migrates the data for the BCD features that are included in each feature to tags within BCD. To run, simply run node --loader=ts-node/esm scripts/migrate-to-bcd.ts ../browser-compat-data or npx tsx scripts/migrate-to-bcd.ts ../browser-compat-data.

The key difference between this PR and the original is that the BCD path has been replaced to use a relative path by default, which expects the BCD folder to be right next to the web-features folder -- but more importantly, the path can be overridden with the BCD_PATH environment variable.

Closes #473.

[Elchi3]

Thanks Vinyl! The BCD path works great for me.

I think we want to rename the file from migrate.ts to migrate-to-bcd.ts.

The script doesn't handle renames or removals. How hard would it be to implement that? See #1605 that renamed growable-sharedarraybuffer to resizable-buffers, for example. If I run migrate, I end up with

"tags": [
  "web-features:snapshot:ecmascript-2024",
  "web-features:growable-sharedarraybuffer",
  "web-features:resizable-buffers"
],

Desired would be:

"tags": [
  "web-features:snapshot:ecmascript-2024",
  "web-features:resizable-buffers"
],

[Elchi3]

Thanks, that works great for me!

The tags are added to the bottom of the JSON in BCD. Should we run "npm run fix" in BCD in the script somehow to fix that?

[queengooborg]

We could do that, but I think that it'd be better to do so outside of the script -- for example, during a GitHub Actions workflow. What do you think?

[Elchi3]

Either way would be fine with me.
Approving but waiting for another owner to review this PR before merging.

[ddbeck]

Thank you, @queengooborg. Some questions and suggestions in line comments.

[Elchi3]

@queengooborg can you resolve the conflicts here?