Add support for ZSTD compression to roblox.serializeModel and roblox.serializePlace

[Dekkonot]

As of the latest release of rbx-binary, we support specifying the compression type that's used for chunks. By default, this is lz4 which is what Lune currently uses. Roblox's file format also supports zstd however, and it's significantly more space efficient.

We should add an option to control the compression type in some way. Alternatively, we could just swap the default to be zstd instead of lz4. That might be better since it doesn't break the API surface, but I don't know how Roblox would feel about it.

[twang58rbx]

Hi I am a Roblox engineer. We are migrating the chunk compression used by rbxl serialization from l4 to ZSTD for any place files ingested to Roblox cloud (including team create/studio cloud saves). I spoke to @Dekkonot earlier and realized that Lune directly reads place files.
What this means - for lune users, if they get the place file via studio file save, they will get l4 place files, which is supported by lune. If users get place files via the asset delivery URL directly, they will get zstd files.
We would like to know if lune has an established use pattern where users get place files via asset delivery. If so can we make a soft announcement (e.g. in README) to ask lune users get place files via studio before Lune supports reading ZSTD place files officially. Let me know if there is any concerns. Thanks!