WebTransport WASM support

[v1rtl]

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Implements WebAssembly support for the WebTranport transport based on https://github.com/libp2p/go-libp2p/pull/2191

I've also added an example to demonstrate connecting to a remote libp2p WT node, it works in Chrome

live demo: https://bafybeie2gvjhno6djfyohmmubhfi7qtpidli7w2rqpryomd4yq7us6auiq.ipfs.dweb.link/