[esbuild-plugin-compress] Add zstd support

[Daniel15]

Chrome was doing an origin trial of zstd compression, and just shipped it in Chrome v123: https://chromestatus.com/feature/6186023867908096. Mozilla also just landed it in nightly builds (https://github.com/mozilla/standards-positions/issues/775#issuecomment-2049605786)

zstd is faster than Brotli while also usually having a better compression ratio. It would be nice for this plugin to support it.

There are a few Node.js modules that implement zstd, for example https://www.npmjs.com/package/@skhaz/zstd.