Support wasm splitting #1022
Description
Leptos recently added wasm splitting to its toolchain via islands and following the prototype described in wasm-bindgen/wasm-bindgen#3939.
It seems that wasm-bindgen does not, at the moment, consider adding this to their toolchain itself. I'm seemingly not able to hack this in by myself (outside a code change to trunk), due to the hooks in trunk running either too early or too late; The wasm should be split before wasm-bindgen processes it (as that seemingly throws away required relocation information), and produces multiple output artifacts for trunk (that should then, each, be further processed by wasm-opt and other tools as configured).
I would try to hack this together into the trunk pipeline, but let me know if this would be something you consider to have first.