Lazy-load compression filters in H5WasmProvider

[axelboc]

Thanks to the new h5wasm-plugins package (kudos @bmaranville!!), I'm able to load compression plugins on demand in H5WasmProvider. 🎉

I was hoping that everything could be taken care of by H5WasmProvider under the hood, but since @h5web/h5wasm is a library, it's not that simple. The plugin files have to be loaded into Emscripten's file system as array buffers, which means they first have to be fetched lazily somehow ... and only the consumer application knows how to do that:

• perhaps the application is bundled with Vite or webpack, which means the plugins can be imported as static assets (i.e. to get their file system URLs) ` and then fetched as array buffers;
• perhaps the application doesn't use a bundler and just serves the plugin files at known URLs;
• perhaps the application runs in an environment that prevents the use of fetch altogether (e.g. VS Code webview).

The solution I came up with is to expose a getPlugin prop. If the prop is implemented by the consumer app, then it will be called with the name of a known plugin when the time comes to load it into Emscripten. It is then up to the consumer application to return an array buffer (or undefined if the plugin is not supported).

H5WasmProvider holds a mapping of known plugins against their corresponding HDF5 filter IDs. For now, this list will need to be kept up to date as more plugins are added to h5wasm-plugins. In the future, we could add a prop to let consumers declare additional plugins without having to wait for H5Web updates.

This PR brings support for the following 7 compression filters in the h5wasm demo: Blosc, bzip2, LZ4, LZF, SZ, ZFP and Zstandard. You can try it with this file, which comes from the h5wasm-plugins repo: https://www.silx.org/pub/h5web/filters.h5

[loichuder]

Amazing 🤩